UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 35,239	$ 11,500
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred financing costs	83	83
Amortization of investment discount/premium	65	127
Depreciation and amortization	25,733	25,983
Deferred income taxes	(2,108)	10,834
Stock-based compensation	3,025	3,010
Impairment of right-of-use lease assets	453	0
Changes in assets and liabilities:
Tuition receivable, net	3,553	4,847
Other current assets	(3,321)	(1,060)
Other assets	231	325
Accounts payable and accrued expenses	(7,028)	(3,537)
Income taxes payable and income taxes receivable	12,314	6,031
Contract liabilities	1,901	1,702
Other long-term liabilities	(1,445)	(1,187)
Net cash provided by operating activities	68,695	58,658
Cash flows from investing activities:
Purchases of property and equipment	(14,258)	(8,756)
Purchases of marketable securities	(1,863)	(6,249)
Maturities of marketable securities	9,905	12,910
Other investments	(118)	(374)
Net cash used in investing activities	(6,334)	(2,469)
Cash flows from financing activities:
Common dividends paid	(13,327)	(11,091)
Net payments for stock awards	(25,089)	(4,443)
Repurchase of common stock	(247)	0
Net cash used in financing activities	(38,663)	(15,534)
Net increase in cash, cash equivalents, and restricted cash	23,698	40,655
Cash, cash equivalents, and restricted cash — beginning of period	420,497	312,237
Cash, cash equivalents, and restricted cash — end of period	444,195	352,892
Noncash transactions:
Non-cash additions to property and equipment	1,392	634
Right-of-use lease assets obtained in exchange for operating lease liabilities	$ 3,504	$ 1,190