Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenue	$ 327,910	$ 350,020	$ 329,479
Costs and expenses:
Instructional costs and services	118,848	123,765	112,784
Selling and promotional	62,397	69,229	65,687
General and administrative	73,864	75,073	70,063
Depreciation and amortization	20,520	16,121	13,508
Total costs and expenses	275,629	284,188	262,042
Income before interest income and income taxes	52,281	65,832	67,437
Interest income, net	115	361	309
Income from operations before income taxes	52,396	66,193	67,746
Income tax expense	20,072	25,150	25,645
Equity investment income/(loss), net of tax	90	(166)	(67)
Net income	$ 32,414	$ 40,877	$ 42,034
Net income per common share:
Basic (in dollars per share)	$ 1.94	$ 2.36	$ 2.38
Diluted (in dollars per share)	$ 1.93	$ 2.33	$ 2.35
Weighted average number of shares outstanding:
Basic (in shares)	16,676	17,357	17,656
Diluted (in shares)	16,798	17,543	17,921