001 - Statement - Balance Sheets (Unaudited) link:presentationLink link:definitionLink link:calculationLink 002 - Statement - Balance Sheets (Unaudited) (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 003 - Statement - Statements of Income (Unaudited) link:presentationLink link:definitionLink link:calculationLink 004 - Statement - Statements of Common Stockholders' Equity (Unaudited) link:presentationLink link:definitionLink link:calculationLink 005 - Statement - Statements of Common Stockholders' Equity (Unaudited) (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 006 - Statement - Statements of Cash Flows (Unaudited) link:presentationLink link:definitionLink link:calculationLink 007 - Statement - Statements of Cash Flows (Unaudited) (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 008 - Disclosure - Basis of Presentation link:presentationLink link:definitionLink link:calculationLink 009 - Disclosure - Acquisitions link:presentationLink link:definitionLink link:calculationLink 010 - Disclosure - Accounts Receivable and Unbilled Revenue link:presentationLink link:definitionLink link:calculationLink 011 - Disclosure - Common Stock and Earnings Per Share link:presentationLink link:definitionLink link:calculationLink 012 - Disclosure - Debt link:presentationLink link:definitionLink link:calculationLink 013 - Disclosure - Interest Rate Swap Agreement link:presentationLink link:definitionLink link:calculationLink 014 - Disclosure - Fair Value of Financial Instruments link:presentationLink link:definitionLink link:calculationLink 015 - Disclosure - Commitments link:presentationLink link:definitionLink link:calculationLink 016 - Disclosure - Revenue Recognition link:presentationLink link:definitionLink link:calculationLink 017 - Disclosure - Rate Matters link:presentationLink link:definitionLink link:calculationLink 018 - Disclosure - Pensions link:presentationLink link:definitionLink link:calculationLink 019 - Disclosure - Stock-Based Compensation link:presentationLink link:definitionLink link:calculationLink 020 - Disclosure - Income Taxes link:presentationLink link:definitionLink link:calculationLink 996000 - Disclosure - Accounting Policies, by Policy (Policies) link:presentationLink link:definitionLink link:calculationLink 996001 - Disclosure - Accounts Receivable and Unbilled Revenue (Tables) link:presentationLink link:definitionLink link:calculationLink 996002 - Disclosure - Common Stock and Earnings Per Share (Tables) link:presentationLink link:definitionLink link:calculationLink 996003 - Disclosure - Debt (Tables) link:presentationLink link:definitionLink link:calculationLink 996004 - Disclosure - Fair Value of Financial Instruments (Tables) link:presentationLink link:definitionLink link:calculationLink 996005 - Disclosure - Revenue Recognition (Tables) link:presentationLink link:definitionLink link:calculationLink 996006 - Disclosure - Pensions (Tables) link:presentationLink link:definitionLink link:calculationLink 996007 - Disclosure - Stock-Based Compensation (Tables) link:presentationLink link:definitionLink link:calculationLink 996008 - Disclosure - Acquisitions (Details) link:presentationLink link:definitionLink link:calculationLink 996009 - Disclosure - Accounts Receivable and Unbilled Revenue - Accounts Receivable and Unbilled Revenue (Details) link:presentationLink link:definitionLink link:calculationLink 996010 - Disclosure - Common Stock and Earnings Per Share (Details) link:presentationLink link:definitionLink link:calculationLink 996011 - Disclosure - Common Stock and Earnings Per Share - Shares Used in Computing Basic and Diluted Earnings per Share (Details) link:presentationLink link:definitionLink link:calculationLink 996012 - Disclosure - Debt - Debt (Details) link:presentationLink link:definitionLink link:calculationLink 996013 - Disclosure - Interest Rate Swap Agreement (Details) link:presentationLink link:definitionLink link:calculationLink 996014 - Disclosure - Fair Value of Financial Instruments (Details) link:presentationLink link:definitionLink link:calculationLink 996015 - Disclosure - Fair Value of Financial Instruments - Fair Value of Interest Rate Swap (Details) link:presentationLink link:definitionLink link:calculationLink 996016 - Disclosure - Commitments (Details) link:presentationLink link:definitionLink link:calculationLink 996017 - Disclosure - Revenue Recognition (Details) link:presentationLink link:definitionLink link:calculationLink 996018 - Disclosure - Revenue Recognition - Operating Revenues Disaggregated by Service and Customer Type (Details) link:presentationLink link:definitionLink link:calculationLink 996019 - Disclosure - Rate Matters (Details) link:presentationLink link:definitionLink link:calculationLink 996020 - Disclosure - Pensions (Details) link:presentationLink link:definitionLink link:calculationLink 996021 - Disclosure - Pensions - Components of Net Periodic Pension Cost (Details) link:presentationLink link:definitionLink link:calculationLink 996022 - Disclosure - Stock-Based Compensation (Details) link:presentationLink link:definitionLink link:calculationLink 996023 - Disclosure - Stock-Based Compensation - Restricted Stock (Details) link:presentationLink link:definitionLink link:calculationLink 996024 - Disclosure - Income Taxes (Details) link:presentationLink link:definitionLink link:calculationLink 000 - Document - Document And Entity Information link:presentationLink link:definitionLink link:calculationLink