Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income	$ 106,044	$ 131,260	$ 105,078
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on disposal of assets			248
Amortization of gain on sale of assets	(281)	(281)	(281)
Amortization of deferred rent	1,177	275	(108)
Gain on sale of marketable securities	(66)	(406)
Amortization of deferred financing costs	663
Depreciation and amortization	21,525	17,309	13,937
Deferred income taxes	3,722	353	(2,564)
Stock-based compensation	13,234	11,987	10,954
Changes in assets and liabilities:
Tuition receivable, net	(2,995)	(4,233)	5,205
Other current assets	(768)	(1,153)	(232)
Other assets	102	(258)	(896)
Accounts payable and accrued expenses	(3,360)	10,146	5,283
Income taxes payable and income taxes receivable	(1,279)	(1,358)	11,645
Excess tax benefits from stock-based payment arrangements		(2,808)	(3,011)
Unearned tuition	11,841	1,083	(3,957)
Other long-term liabilities	4,804	905	471
Net cash provided by operating activities	154,363	162,821	141,772
Cash flows from investing activities:
Purchases of property and equipment	(29,991)	(46,015)	(30,431)
Purchases of marketable securities	(2)	(559)	(1,085)
Proceeds from the sale of marketable securities	12,388	40,700
Acquisition of assets	(7,000)
Net cash used in investing activities	(24,605)	(5,874)	(31,516)
Cash flows from financing activities:
Common dividends paid	(49,105)	(44,541)	(31,627)
Proceeds from exercise of stock options		452	6,027
Excess tax benefits from stock-based payment arrangements		2,808	3,011
Repurchase of common stock	(202,664)	(115,517)	(80,088)
Proceeds from revolving credit facility	120,000
Payments on revolving credit facility	(100,000)
Proceeds from term loan	100,000
Payments on term loan	(2,500)
Payment of deferred financing costs	(2,459)
Net cash used in financing activities	(136,728)	(156,798)	(102,677)
Net increase (decrease) in cash and cash equivalents	(6,970)	149	7,579
Cash and cash equivalents - beginning of year	64,107	63,958	56,379
Cash and cash equivalents - end of year	57,137	64,107	63,958
Non-cash transactions:
Purchases of property and equipment included in accounts payable	$ 1,115	$ 5,508	$ 2,917