CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Total revenue	$ 860,969	$ 704,589	$ 436,152
Operating expenses:
Direct service costs, excluding depreciation and amortization	321,006	252,284	211,773
Reimbursed out-of-pocket expenses	294,266	236,775	49,690
Total direct costs	615,272	489,059	261,463
Selling, general and administrative	95,245	75,681	63,357
Depreciation	8,360	9,240	8,574
Amortization	14,829	29,561	37,900
Total operating expenses	733,706	603,541	371,294
Income from operations	127,263	101,048	64,858
Other expense, net:
Miscellaneous (expense) income, net	(863)	1,060	(354)
Interest expense, net	(1,568)	(8,157)	(7,559)
Total other expense, net	(2,431)	(7,097)	(7,913)
Income before income taxes	124,832	93,951	56,945
Income tax provision	24,389	20,766	17,823
Net income	$ 100,443	$ 73,185	$ 39,122
Net income per share attributable to common shareholders:
Basic	$ 2.79	$ 2.05	$ 1.00
Diluted	$ 2.67	$ 1.97	$ 0.98
Weighted average common shares outstanding:
Basic	35,881	35,547	39,056
Diluted	37,576	36,912	39,839
Revenue Net
Revenue:
Total revenue	$ 860,969	$ 704,589	$ 0
Direct Service Revenue
Revenue:
Total revenue	0	0	386,462
Reimbursed Out of Pocket Revenue
Revenue:
Total revenue	$ 0	$ 0	$ 49,690