Quarterly Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended									12 Months Ended
	Oct. 01, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Gross profit		$ 23,309	$ 21,667	$ 22,959	$ 21,278	$ 18,292	$ 19,199	$ 22,573	$ 17,679		$ 89,213	$ 77,743	$ 82,027
Net income		$ 9,495	$ 2,141	$ 3,219	$ 334	$ 385	$ 3,244	$ 3,575	$ 2,632		$ 15,189	$ 9,836	$ 12,891
Earnings per share:
Basic earnings per share (in dollars per share)		$ 0.56	$ 0.13	$ 0.19	$ 0.02	$ 0.02	$ 0.20	$ 0.22	$ 0.16		$ 0.90	$ 0.59	$ 0.77
Diluted (in dollars per share)		$ 0.56	$ 0.13	$ 0.19	$ 0.02	$ 0.02	$ 0.20	$ 0.22	$ 0.16		$ 0.90	$ 0.59	$ 0.76
Revenue and gross profit reduction related to contract										$ 2,600
Revenue from External Customer [Line Items]
Revenue			$ 139,005	$ 149,413	$ 139,473	$ 132,871	$ 123,566	$ 133,691	$ 125,032		$ 583,290	$ 515,160	$ 509,208
Revenue		$ 155,399									583,290	515,160	509,208
Gain on sale of business											$ 12,126	$ 0	$ 0
Tuition Program Management Business
Revenue from External Customer [Line Items]
Gain on sale of business	$ 12,100