Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows provided by operating activities:
Net income	$ 69,447	$ 50,546	$ 35,206
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation	7,811	6,452	5,049
Excess tax benefits from share-based compensation	(1,427)		(736)
Amortization of notes payable issuance costs	244	80	63
Provision for bad debts	18,012	34,364	38,511
Depreciation and amortization	21,923	17,034	12,108
Loss on asset disposal	1,106
Non-capitalizable system conversion costs			4,013
Exit costs		(64)	(768)
Lease termination fees		782
Deferred income taxes	(518)	20,794	(6,013)
Other		92	23
Changes in assets and liabilities:
Restricted cash and cash equivalents	151	(9,137)	(43,706)
Accounts receivable	(14,148)	(28,196)	(46,705)
Prepaid expenses and other	(1,920)	(6,158)	(5,536)
Due to/from related parties	296	(9,244)	9,166
Accounts payable	(630)	3,155	2,510
Accrued liabilities	15,719	(3,300)	5,013
Accrued litigation loss		(5,200)
Income taxes receivable/payable	20,593	(3,599)	(9,293)
Deferred rent	503	4,143	790
Deferred revenue	6,891	6,689	(3,021)
Student deposits	143	8,729	43,724
Net cash provided by operating activities	144,196	87,962	40,398
Cash flows used in investing activities:
Capital expenditures	(97,653)	(80,545)	(62,627)
Purchase of land and building related to future development	(7,223)
Investment in note receivable secured by real estate	(27,000)
Restricted funds held for derivative collateral and legal matter	330	5,405	(5,960)
Proceeds from sale or maturity of investments			487
Net cash used in investing activities	(131,546)	(75,140)	(68,100)
Cash flows provided by (used in) financing activities:
Principal payments on notes payable and capital lease obligations	(21,744)	(3,748)	(2,933)
Proceeds from notes payable	99,210
Notes payable modification costs	(428)	(91)
Repurchase of common shares	(15,242)	(23,112)	(782)
Net proceeds from exercise of stock options	8,049	1,681	1,747
Excess tax benefits from share-based compensation	1,427		736
Net cash provided by (used in) financing activities	71,272	(25,270)	(1,232)
Net increase (decrease) in cash and cash equivalents	83,922	(12,448)	(28,934)
Cash and cash equivalents, beginning of year	21,189	33,637	62,571
Cash and cash equivalents, end of year	105,111	21,189	33,637
Supplemental disclosure of cash flow information
Cash paid during the year for interest	606	535	769
Cash paid during the year for income taxes	32,810	13,463	37,703
Supplemental disclosure of non-cash investing and financing activities
Purchase of equipment through notes payable and capital lease obligations		801	957
Purchases of property and equipment included in accounts payable and deferred rent	3,291	325	4,421
Shortfall tax expense from share-based compensation	283	151
Tax benefit of Spirit warrant intangible	$ 267	$ 291	$ 182