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 FROM OPERATING ACTIVITIES:
Net income	$ 156,761	$ 162,510	$ 157,193
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	113,933	108,931	106,273
Goodwill impairment			1,684
Amortization of debt issuance costs and other non-cash interest	4,316	4,331	4,250
Expenses associated with debt refinancing transactions	2,099
Deferred income taxes	5,761	19,321	26,203
Other expenses and non-cash items	1,084	1,559	645
Income tax benefit of equity compensation	(2,708)	(1,962)	(4,371)
Non-cash equity compensation	12,325	10,384	9,646
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	12,189	46,941	(70,964)
Accounts payable, accrued expenses and other liabilities	(24,219)	(2,456)	21,049
Income taxes payable	1,715	1,517	3,907
Net cash provided by operating activities	283,256	351,076	255,515
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility acquisition, development and expansions	(30,424)	(125,682)	(101,820)
Expenditures for other capital improvements	(49,014)	(48,258)	(41,843)
Decrease in restricted cash		1,749
Proceeds from sale of assets	1,838	885	86
Increase in other assets	(4,027)	(2,248)	(1,875)
Payments received on direct financing lease and notes receivable	1,707	1,515	1,229
Net cash used in investing activities	(79,920)	(172,039)	(144,223)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	888,500	383,623	171,167
Principal repayments of debt	(1,023,500)	(296,589)	(165,000)
Payment of debt issuance and other refinancing and related costs	(6,336)
Proceeds from exercise of stock options	4,933	2,137	6,601
Purchase and retirement of common stock	(2,808)	(239,847)	(148,830)
Income tax benefit of equity compensation	2,708	1,962	4,371
Dividends paid	(59,768)
Net cash used in financing activities	(196,271)	(148,714)	(131,691)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	7,065	30,323	(20,399)
CASH AND CASH EQUIVALENTS, beginning of year	55,832	25,509	45,908
CASH AND CASH EQUIVALENTS, end of year	62,897	55,832	25,509
Cash paid during the period for:
Interest (net of amounts capitalized of $1,057, $1,584, and $3,922 in 2012, 2011, and 2010, respectively)	66,943	71,002	69,121
Income taxes	$ 83,864	$ 70,341	$ 61,396