Consolidated Statements of Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 1,027,653	$ 997,137	$ 634,185
Costs and expenses:
Instructional and support costs	532,661	530,604	371,542
General and administration	295,231	272,411	194,035
Amortization of intangible assets	64,225	61,667	25,694
Merger and integration costs	13,770	21,923	45,745
Restructuring costs	12,382	0	0
Impairment of intangible assets	0	0	19,909
Total costs and expenses	918,269	886,605	656,925
Income (loss) from operations	109,384	110,532	(22,740)
Other income	4,573	13,192	3,601
Income (loss) before income taxes	113,957	123,724	(19,139)
Provision (benefit) for income taxes	27,689	42,586	(3,468)
Net income (loss)	$ 86,268	$ 81,138	$ (15,671)
Earnings (loss) per share:
Basic (dollars per share)	$ 3.81	$ 3.73	$ (1.03)
Diluted (dollars per share)	$ 3.77	$ 3.67	$ (1.03)
Weighted average shares outstanding:
Basic (in shares)	22,633	21,725	15,190
Diluted (in shares)	22,860	22,097	15,190