CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income (loss)	$ (27,024)	$ 138,970	$ 309,086
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	27,252	29,350	27,886
Provision for doubtful accounts	67,640	56,818	35,655
Deferred income taxes	(54,425)	(59,999)	(8,991)
Excess tax benefit from stock option exercises	0	(1,382)	(1,166)
Stock-based compensation expense	11,638	16,658	17,074
Settlement cost	(46,000)	21,750	0
Asset impairment	0	15,166	0
Provision for PEAKS Trust student loan losses	29,349	0	0
Loss on consolidation of PEAKS Trust	73,248	0	0
Other	315	6,992	(1,936)
Changes in operating assets and liabilities, net of acquisition:
Restricted cash	(455)	3,794	(942)
Accounts receivable	(87,225)	(87,138)	(17,004)
PEAKS Trust student loans	11,554	0	0
Accounts payable	(5,574)	(15,572)	10,956
Other operating assets and liabilities	74,203	72,857	35,964
Deferred revenue	11,299	(90,643)	(17,819)
Net cash flows from operating activities	77,725	107,621	388,763
Cash flows from investing activities:
Facility expenditures and land purchases	(679)	(1,046)	(4,053)
Capital expenditures, net	(4,468)	(17,204)	(26,847)
Acquisition of company, net of cash acquired	(7,150)	0	0
Proceeds from sales and maturities of investments and repayment of notes	461	217,301	337,032
Purchase of investments and note advances	(1,242)	(75,887)	(352,195)
Net cash flows from investing activities	(13,078)	123,164	(46,063)
Cash flows from financing activities:
Excess tax benefit from stock option exercises	0	1,382	1,166
Proceeds from exercise of stock options	0	8,345	5,599
Debt issue costs	0	(1,525)	0
Proceeds from revolving borrowings	0	175,000	0
Repayment of revolving borrowings	(90,000)	(185,000)	0
Repayment of PEAKS Trust senior debt	(1,946)	0	0
Repurchase of common stock and shares tendered for taxes	(395)	(209,371)	(283,320)
Net cash flows from financing activities	(92,341)	(211,169)	(276,555)
Net change in cash and cash equivalents	(27,694)	19,616	66,145
Cash and cash equivalents at beginning of period	243,465	223,849	157,704
Cash and cash equivalents at end of period	215,771	243,465	223,849
Cash paid during the period for:
Income taxes (net of refunds)	61,131	139,919	196,387
Interest	3,310	3,047	1,842
Non-cash operating activities:
Consolidation of PEAKS Trust assets	113,819	0	0
Consolidation of PEAKS Trust liabilities	471	0	0
Non-cash financing activities:
Issuance of treasury stock for Directors' compensation	0	37	30
Consolidation of PEAKS Trust senior debt	226,096	0	0
PEAKS Trust Student Loans [Member]
Adjustments to reconcile net income to net cash flows from operating activities:
Asset impairment		10,300
Accretion of discount on PEAKS Trust	(12,996)	0	0
Provision for PEAKS Trust student loan losses	29,349
Loss on consolidation of PEAKS Trust	(73,248)
PEAKS Trust senior debt [Member]
Adjustments to reconcile net income to net cash flows from operating activities:
Accretion of discount on PEAKS Trust	$ 4,926	$ 0	$ 0