Entity tax identification number Entity Tax Identification Number Participant rollovers EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover EBP, Employer Contribution, Vesting [Domain] EBP, Employer Contribution, Vesting [Domain] EBP, Employer Contribution, Vesting [Domain] Maximum Maximum [Member] Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Mutual funds Mutual Fund [Member] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] Maximum annual compensation to total compensation, percentage EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Maximum borrowing amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Fair Value Measurements EBP, Investment, Fair Value and NAV [Text Block] Minimum borrowing amount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount Total investments Investment, common stock value EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Level 1 Fair Value, Inputs, Level 1 [Member] EBP, Employer Contribution, Vesting [Axis] EBP, Employer Contribution, Vesting [Axis] EBP, Employer Contribution, Vesting EBP, Investment, Fair Value and NAV [Abstract] Assets EBP, Asset [Abstract] Vesting Schedule of Employer Contribution EBP, Employer Contribution, Vesting Schedule [Table Text Block] EBP, Employer Contribution, Vesting Schedule Statistical Measurement [Axis] Statistical Measurement [Axis] Investment Activity & Additions EBP, Change in Net Asset Available for Benefit, Increase [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Benefits Paid to Participants & Contributions EBP, Payment to Participant [Policy Text Block] Transfer in Total net assets transferred into the Plan Net assets transferred into the Plan EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan Amendment Flag Amendment Flag Basis of Accounting EBP, Basis of Accounting [Policy Text Block] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Hire date prior to January 1, 2018, immediately EBP, Vesting Schedule, Tranche One [Member] EBP, Vesting Schedule, Tranche One Investment, number of common stock (in shares) EBP, Investment, Number of Shares EBP, Description of Plan and Accounting Change [Abstract] Schedule of Investment at Fair Value and NAV EBP, Investment, Fair Value and NAV [Table Text Block] Employer contribution, requisite service period EBP, Employer Contribution Vesting, Requisite Service Period EBP, Employer Contribution Vesting, Requisite Service Period Investments [Domain] Investments [Domain] Use of Estimates EBP, Use of Estimate [Policy Text Block] Form 5500, Schedule H, Part IV, Line 4(i) Schedule of Assets (Held at End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Employer matching EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash Minimum Minimum [Member] Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Investment Type [Axis] Investment Type [Axis] Hire date January 1, 2018 or after, less than two years of service EBP, Vesting Schedule, Tranche Two [Member] EBP, Vesting Schedule, Tranche Two Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Participant elective deferral EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Interest and dividend income EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] Plan Description EBP, Description of Plan [Text Block] Minimum age to participate EBP, Minimum Age To Participate EBP, Minimum Age To Participate EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] SPS Commerce, Inc. common stock EBP, Employer, Common Stock [Member] Involuntary transfer to a qualified plan limit EBP, Involuntary Transfer To A Qualified Plan, Limit EBP, Involuntary Transfer To A Qualified Plan, Limit EBP, Schedule of Asset Held for Investment [Abstract] EBP, Accounting Policy [Table] EBP, Accounting Policy [Table] Total investment activity and additions EBP, Change in Net Asset Available for Benefit, Increase Investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Asset held for investment EBP, Asset Held for Investment Involuntary cash-out limit EBP, Involuntary Cash-out Limit EBP, Involuntary Cash-out Limit Risk and Uncertainties and Concentration of Market Risk EBP, Risk and Uncertainty [Policy Text Block] Document Information [Line Items] Document Information [Line Items] Compensation matched percentage EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Vesting Percentage EBP, Employer Contribution, Vesting Percentage EBP, Employer Contribution, Vesting Percentage Number of borrowing EBP, Note Receivable From Participant, Number Of Loans Allowed EBP, Note Receivable From Participant, Number Of Loans Allowed EBP, Tax Status [Table] EBP, Tax Status [Table] Net increase in net assets available for benefits EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Total receivables EBP, Receivable Hire date January 1, 2018 or after, two years or more of service EBP, Vesting Schedule, Tranche Three [Member] EBP, Vesting Schedule, Tranche Three Automatic deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Investments, at fair value EBP, Investment, Fair Value [Abstract] Benefits paid to participants EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Asset held for investment, current value EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] Non-interest bearing cash EBP, Noninterest-Bearing Cash Borrowing term EBP, Note Receivable From Participant, Borrowing Term EBP, Note Receivable From Participant, Borrowing Term Administrative Expenses EBP, Expense [Policy Text Block] Participant loans, current value EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Investment Valuation and Income (Loss) Recognition EBP, Investment [Policy Text Block] EBP 001 EBP 001 [Member] EBP 001 Fair Value, Inputs, Level 1, Level 2, and Level 3 Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Document Type Document Type Entity Central Index Key Entity Central Index Key Requisite service period EBP, Requisite Service Period EBP, Requisite Service Period Interest rate EBP, Asset Held for Investment, Participant Loan, Interest Rate Common collective trust funds Common Collective Trust [Member] Net assets available for benefits EBP, Net Asset Available for Benefit [Abstract] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Deductions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Notes receivable from participants EBP, Note Receivable from Participant Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Concentration of employer's common stock to net assets, percentage EBP, Risk and Uncertainty, Concentration of Investment at Fair Value to Net Assets, Percentage Income Tax Status EBP, Tax Status [Text Block] Maximum borrowing to total account, percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Document Information [Table] Document Information [Table] Participant loans, cost EBP, Asset Held for Investment, Participant Loan, Cost EBP, Asset Held for Investment, Participant Loan, Cost Notes Receivable from Participants EBP, Note Receivable from Participant [Policy Text Block] Net investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Level 3 Fair Value, Inputs, Level 3 [Member] Other receivables EBP, Other Receivable Net assets available for benefits Beginning of year End of year EBP, Net Asset Available for Benefit Entity [Domain] Entity [Domain] Contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Employer contribution, matching percentage EBP, Employer Contribution, Matching Percentage NAV Fair Value Measured at Net Asset Value Per Share [Member] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items]