Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 25,639,000	$ 21,121,000	$ 24,155,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	17,501,000	18,776,000	19,384,000
Stock-based compensation	7,180,000	6,246,000	5,211,000
Equity investment loss/(income)	515,000	2,430,000	(703,000)
Deferred income taxes	(917,000)	(2,494,000)	(455,000)
Loss on disposals of long-lived assets	882,000	2,093,000	5,970,000
Impairment of goodwill	0	0	4,735,000
Other	302,000	353,000	329,000
Changes in operating assets and liabilities:
Accounts receivable, net of allowance for bad debt	(6,923,000)	(187,000)	968,000
Prepaid expenses	(560,000)	571,000	1,102,000
Income tax receivable	(898,000)	0	0
Other assets	71,000	(653,000)	(105,000)
Accounts payable	266,000	1,991,000	589,000
Accrued compensation and benefits	3,298,000	(1,455,000)	3,327,000
Accrued liabilities	875,000	(740,000)	(3,751,000)
Income tax payable	(1,710,000)	1,151,000	(123,000)
Deferred revenue and student deposits	(1,342,000)	(1,265,000)	(4,619,000)
Net cash provided by operating activities	44,179,000	47,938,000	56,014,000
Investing activities
Capital expenditures	(9,430,000)	(14,788,000)	(16,399,000)
Proceeds from the sale of real property	0	1,493,000	844,000
Equity investments	0	(300,000)	(950,000)
Dividend received from equity investment	0	0	2,957,000
Net cash used in investing activities	(9,430,000)	(13,595,000)	(13,548,000)
Financing activities
Cash paid for repurchase of common/restricted stock	(1,823,000)	(1,587,000)	(848,000)
Cash received from issuance of common stock	0	98,000	119,000
Excess tax expense from stock-based compensation	0	0	(1,120,000)
Net cash used in financing activities	(1,823,000)	(1,489,000)	(1,849,000)
Net increase in cash, cash equivalents, and restricted cash	32,926,000	32,854,000	40,617,000
Cash, cash equivalents, and restricted cash at beginning of period	179,205,000	146,351,000	105,734,000
Cash, cash equivalents, and restricted cash at end of period	212,131,000	179,205,000	146,351,000
Supplemental disclosures of cash flow information
Income taxes paid	$ 12,712,000	$ 12,836,000	$ 16,637,000