Consolidated Statements of Income - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenue	$ 82,127,000	$ 70,560,000	$ 156,743,000	$ 144,001,000
Costs and expenses:
Instructional costs and services	30,744,000	28,725,000	59,974,000	56,640,000
Selling and promotional	17,056,000	14,087,000	35,242,000	29,134,000
General and administrative	21,737,000	18,123,000	42,740,000	37,188,000
Loss on disposals of long-lived assets	158,000	4,000	324,000	130,000
Impairment of goodwill	0	0	0	5,855,000
Depreciation and amortization	3,391,000	3,943,000	6,729,000	7,994,000
Total costs and expenses	73,086,000	64,882,000	145,009,000	136,941,000
Income from operations before interest income and income taxes	9,041,000	5,678,000	11,734,000	7,060,000
Interest income, net	179,000	1,135,000	881,000	2,188,000
Income before income taxes	9,220,000	6,813,000	12,615,000	9,248,000
Income tax expense	2,532,000	1,898,000	3,506,000	1,835,000
Equity investment income (loss)	1,000	6,000	0	(1,481,000)
Net income	$ 6,689,000	$ 4,921,000	$ 9,109,000	$ 5,932,000
Net income per common share:
Basic (in dollars per share)	$ 0.45	$ 0.30	$ 0.61	$ 0.36
Diluted (in dollars per share)	$ 0.45	$ 0.30	$ 0.61	$ 0.36
Weighted average number of common shares:
Basic (in shares)	14,789	16,512	14,907	16,522
Diluted (in shares)	14,948	16,653	15,026	16,671