Consolidated Statements of Income - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 79,133,000	$ 67,888,000	$ 235,876,000	$ 211,889,000
Costs and expenses:
Instructional costs and services	31,084,000	27,268,000	91,058,000	83,908,000
Selling and promotional	18,523,000	15,873,000	53,765,000	45,007,000
General and administrative	22,574,000	22,021,000	65,314,000	59,209,000
Loss on disposals of long-lived assets	418,000	394,000	742,000	524,000
Impairment of goodwill	0	1,481,000	0	7,336,000
Depreciation and amortization	3,226,000	3,764,000	9,955,000	11,758,000
Total costs and expenses	75,825,000	70,801,000	220,834,000	207,742,000
Income (loss) from operations before interest income and income taxes	3,308,000	(2,913,000)	15,042,000	4,147,000
Interest income, net	121,000	1,019,000	1,002,000	3,207,000
Income (loss) before income taxes	3,429,000	(1,894,000)	16,044,000	7,354,000
Income tax expense (benefit)	785,000	(239,000)	4,291,000	1,596,000
Equity investment income (loss)	(2,000)	17,000	(2,000)	(1,464,000)
Net income (loss)	$ 2,642,000	$ (1,638,000)	$ 11,751,000	$ 4,294,000
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.18	$ (0.10)	$ 0.79	$ 0.26
Diluted (in dollars per share)	$ 0.18	$ (0.10)	$ 0.78	$ 0.26
Weighted average number of common shares:
Basic (in shares)	14,797	15,967	14,870	16,335
Diluted (in shares)	15,011	16,121	15,021	16,487