Consolidated Statements of Income - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 418,803,000	$ 321,785,000	$ 286,270,000
Costs and expenses:
Instructional costs and services	172,622,000	122,161,000	111,916,000
Selling and promotional	93,317,000	72,989,000	60,028,000
General and administrative	103,379,000	88,043,000	78,082,000
Loss on disposals of long-lived assets	1,282,000	851,000	556,000
Impairment of goodwill	0	0	7,336,000
Depreciation and amortization	17,832,000	12,984,000	15,596,000
Total costs and expenses	388,432,000	297,028,000	273,514,000
Income from operations before interest and income taxes	30,371,000	24,757,000	12,756,000
Interest income (expense)	(4,277,000)	1,092,000	3,908,000
Income from operations before income taxes	26,094,000	25,849,000	16,664,000
Income tax expense	7,511,000	7,020,000	5,187,000
Equity investment loss	(831,000)	(7,000)	(1,464,000)
Net income	$ 17,752,000	$ 18,822,000	$ 10,013,000
Net income per common share:
Basic (in dollars per share)	$ 0.98	$ 1.27	$ 0.62
Diluted (in dollars per share)	$ 0.97	$ 1.25	$ 0.62
Weighted average number of shares outstanding:
Basic (in shares)	18,085	14,876	16,094
Diluted (in shares)	18,255	15,047	16,255