CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue, net (includes $34.5 million, $15.9 million and $18.9 million with related parties for the years ended December 31, 2021, 2020 and 2019, respectively)	$ 1,142,377	$ 925,925	$ 860,969
Operating expenses:
Total direct costs	814,222	647,199	615,272
Selling, general and administrative	108,421	92,156	95,245
Depreciation	16,005	11,652	8,360
Amortization	5,114	7,876	14,829
Total operating expenses	943,762	758,883	733,706
Income from operations	198,615	167,042	127,263
Other income (expense), net:
Miscellaneous income (expense), net	3,342	1,183	(863)
Interest (expense) income, net	(105)	(307)	(1,568)
Total other income (expense), net	3,237	(1,490)	(2,431)
Income before income taxes	201,852	168,532	124,832
Income tax provision	20,004	23,148	24,389
Net income	$ 181,848	$ 145,384	$ 100,443
Net income per share attributable to common shareholders:
Basic	$ 5.06	$ 4.07	$ 2.79
Diluted	$ 4.81	$ 3.84	$ 2.67
Weighted average common shares outstanding:
Basic	35,862	35,635	35,881
Diluted	37,697	37,708	37,576
Direct Costs
Operating expenses:
Total direct costs	$ 441,090	$ 354,426	$ 321,006
Reimbursable Out of Pocket Costs
Operating expenses:
Total direct costs	$ 373,132	$ 292,773	$ 294,266