Business Segments (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($) practice_area	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment practice_area	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of Reportable Segments | segment									2
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	4								4
Revenue	$ 132,871	$ 123,566	$ 133,691	$ 125,032	$ 131,503	$ 124,097	$ 131,161	$ 122,447	$ 515,160	$ 509,208	$ 490,559
Total gross profit	$ 18,292	$ 19,199	$ 22,573	$ 17,679	$ 21,558	$ 18,646	$ 22,435	$ 19,388	77,743	82,027	80,157
General and Administrative Expense									54,848	55,753	47,162
Selling and Marketing Expense									4,798	1,666	1,435
Restructuring charges									2,930	3,317	0
Gain (loss) on change in fair value of contingent consideration, net									(4,438)	(1,620)	136
Operating income									19,605	22,911	31,424
Interest expense									(2,945)	(3,132)	(1,568)
Other (expense) income									(1,897)	(90)	178
Income before income taxes									$ 14,763	19,689	30,034
Workforce Excellence [Member]
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	2								2
Revenue									$ 316,814	308,259	305,915
Total gross profit									$ 50,875	52,958	53,355
Business Transformation Services [Member]
Segment Reporting Information [Line Items]
Number of Practice Areas | practice_area	2								2
Revenue									$ 198,346	200,949	184,644
Total gross profit									$ 26,868	$ 29,069	$ 26,802