v3.26.3
Segment Information - Segment Reporting Information, by Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Jun. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]                
Total operating revenue $ 1,069,917     $ 1,066,739     $ 3,171,624 $ 3,116,235
Total operating expenses 862,535     857,818     2,593,332 2,556,765
Operating income 207,382     208,921     578,292 559,470
Total investment income 19,877     21,554     64,549 60,690
Other income 5,496     2,286     8,317 8,094
Income tax expense 50,766     49,908     138,401 132,299
Net income 181,989 $ 180,294 $ 150,474 182,853 $ 174,685 $ 138,417 $ 512,757 $ 495,955
Erie Insurance Exchange                
Segment Reporting [Line Items]                
Depreciation and amortization expense reimbursed from the Exchange and its insurance subsidiaries (as a percent)             33.00% 30.00%
Management Operations                
Segment Reporting [Line Items]                
Total operating revenue 1,069,917     1,066,739     $ 3,171,624 $ 3,116,235
Commissions 485,486     461,513     1,458,439 1,361,815
Personnel costs 87,013     85,417     267,885 261,195
Sales and advertising 6,848     5,056     19,814 21,737
Acquisition and underwriting support costs 24,036     29,819     72,128 83,660
Technology infrastructure costs 30,384     23,455     81,273 73,837
Professional fees 19,707     19,842     58,219 70,310
Administrative and other 11,499     17,022     36,362 45,600
Total operating expenses 862,535     857,818     2,593,332 2,556,765
Operating income 207,382     208,921     578,292 559,470
Total investment income 19,877     21,554     64,549 60,690
Other income 5,496     2,286     8,317 8,094
Income tax expense 50,766     49,908     138,401 132,299
Net income 181,989     182,853     512,757 495,955
Depreciation and amortization expense 20,700     18,400     61,500 50,300
Management fee revenue | Management Operations                
Segment Reporting [Line Items]                
Total operating revenue 866,700     844,106     2,555,072 2,458,949
Administrative services reimbursement revenue                
Segment Reporting [Line Items]                
Total operating revenue 197,562     215,694     599,212 638,611
Total operating expenses 197,562     215,694     599,212 638,611
Administrative services reimbursement revenue | Management Operations                
Segment Reporting [Line Items]                
Total operating revenue 197,562     215,694     599,212 638,611
Total operating expenses 197,562     215,694     599,212 638,611
Service agreement revenue                
Segment Reporting [Line Items]                
Total operating revenue 5,655     6,939     17,340 18,675
Service agreement revenue | Management Operations                
Segment Reporting [Line Items]                
Total operating revenue 5,655     6,939     17,340 18,675
Cost of operations - policy issuance and renewal services                
Segment Reporting [Line Items]                
Total operating revenue 846,980     825,275     2,496,258 2,404,177
Total operating expenses 664,973     642,124     1,994,120 1,918,154
Cost of operations - policy issuance and renewal services | Management Operations                
Segment Reporting [Line Items]                
Total operating expenses $ 664,973     $ 642,124     $ 1,994,120 $ 1,918,154