Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 171,412	$ 147,953
Cost of services:
Compensation	67,455	57,452
Direct project and other operating expenses	24,895	20,199
Information technology	14,903	13,105
Occupancy	4,362	4,079
Amortization of acquisition related software and intangible assets	5,505	4,166
Total cost of services	117,120	99,001
Selling, general and administrative expenses	35,839	29,246
Total operating expenses	152,959	128,247
Operating income	18,453	19,706
Interest expense	(2,262)	(2,849)
Interest income	234	1,114
Other income	652	0
Income before income taxes	17,077	17,971
Income taxes	4,395	(1,671)
Net income	$ 12,682	$ 19,642
Basic income per common share:
Net income per common share -- basic (in dollars per share)	$ 0.14	$ 0.23
Diluted income per common share:
Net income per common share -- diluted (in dollars per share)	$ 0.14	$ 0.22
Weighted average shares:
Basic (in shares)	88,202	85,853
Diluted (in shares)	89,601	88,614