Segment Reporting (Segment Reporting Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues:
Revenues	$ 1,049,000	$ 1,128,800
Gross Profit:
Total Gross Profit	296,200	326,400
Operating Income (Loss):
Total Operating Income	70,900	84,200
Depreciation	9,400	6,800
Amortization of intangible assets	15,100	18,100
Cloud Based Application
Operating Income (Loss):
Amortization of intangible assets	1,300
Commercial Business
Revenues:
Revenues	731,500	832,100
Gross Profit:
Total Gross Profit	233,800	262,400
Operating Income (Loss):
Total Operating Income	68,800	83,900
Depreciation	7,200	4,600
Amortization of intangible assets	7,700	8,800
Federal Government Business
Revenues:
Revenues	317,500	296,700
Gross Profit:
Total Gross Profit	62,400	64,000
Operating Income (Loss):
Total Operating Income	23,000	22,600
Depreciation	1,700	1,400
Amortization of intangible assets	7,400	9,300
Assignment | Commercial Business
Revenues:
Revenues	454,500	560,400
Consulting | Commercial Business
Revenues:
Revenues	277,000	271,700
Firm-fixed-price | Federal Government Business
Revenues:
Revenues	89,200	92,800
Time and materials | Federal Government Business
Revenues:
Revenues	131,200	121,900
Cost reimbursable | Federal Government Business
Revenues:
Revenues	$ 97,100	$ 82,000