Fair Value Measurements (Note)	3 Months Ended
Fair Value Measurements (Note)	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Recurring Fair Value Measurements — The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and accrued payroll and contract professional pay approximate their fair value based on their short-term nature. The carrying amount of long-term debt recorded in the Company’s balance sheet at March 31, 2022 was $1.0 billion (see Note 5. Long-Term Debt) and its fair value was $1.0 billion, which was determined using quoted prices in active markets for identical liabilities (Level 1 inputs). Certain acquisitions contain provisions requiring the Company to pay contingent consideration in the event the acquired business achieves certain specified earnings results in 2021 or obtains specified contract awards. Contingent consideration liabilities had a fair value of $15.1 million at December 31, 2021. In the three months ended March 31, 2022, $8.1 million of that liability was paid and is reflected in cash flows from financing activities in the accompanying condensed consolidated statement of cash flows. At March 31, 2022, contingent consideration liabilities had a fair value of $7.0 million. Nonrecurring Fair Value Measurements — Certain assets, such as goodwill and trademarks, are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances, such as, when there is evidence of impairment. There were no fair value adjustments for non-financial assets or liabilities during the three months ended March 31, 2022.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.