Business Segments (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($) practice_area	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment practice_area	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting [Abstract]
Number of Reportable Segments | segment									2
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	4								4
Revenue		$ 139,005	$ 149,413	$ 139,473	$ 132,871	$ 123,566	$ 133,691	$ 125,032	$ 583,290	$ 515,160	$ 509,208
Total gross profit	$ 23,309	$ 21,667	$ 22,959	$ 21,278	$ 18,292	$ 19,199	$ 22,573	$ 17,679	89,213	77,743	82,027
General and Administrative Expense									64,492	54,848	55,753
Sales and marketing expenses									7,875	4,798	1,666
Restructuring charges									1,639	2,930	3,317
Gain (loss) on change in fair value of contingent consideration, net									(677)	(4,438)	(1,620)
Gain on sale of business									12,126	0	0
Operating income									28,010	19,605	22,911
Interest expense											(3,132)
Other income (expense)									417	(1,897)	(90)
Income before income taxes									$ 22,369	14,763	19,689
Workforce Excellence [Member]
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	2								2
Total gross profit									$ 55,855	50,875	52,958
Business Transformation Services [Member]
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	2								2
Total gross profit									$ 33,358	26,868	29,069
Operating Segments [Member] | Workforce Excellence [Member]
Segment Reporting Information [Line Items]
Revenue									329,795	316,814	308,259
Operating Segments [Member] | Business Transformation Services [Member]
Segment Reporting Information [Line Items]
Revenue									$ 253,495	$ 198,346	$ 200,949