Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 219,919	$ 221,854	$ 195,022
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	166,746	151,514	113,925
Asset impairments	0	955	30,082
Amortization of debt issuance costs and other non-cash interest	3,147	2,973	3,102
Expenses associated with debt refinancing transactions	0	701	0
Deferred income taxes	(3,911)	5,706	(3,211)
Other expenses and non-cash items	5,265	3,732	4,594
Non-cash revenue and other income	(8,518)	(2,639)	(3,880)
Income tax benefit of equity compensation	(1,479)	(525)	(665)
Non-cash equity compensation	17,903	15,394	13,975
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	14,059	1,266	(12,549)
Accounts payable, accrued expenses and other liabilities	(39,403)	(2,210)	82,396
Income taxes payable	1,645	1,077	790
Net cash provided by operating activities	375,373	399,798	423,581
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(41,816)	(164,880)	(85,791)
Expenditures for other capital improvements	(51,647)	(59,414)	(49,315)
Capitalized lease payments	0	(34,470)	(70,793)
Acquisition of businesses, net of cash acquired	(43,769)	(158,366)	0
Decrease in restricted cash	240	1,350	2,983
Proceeds from sale of assets	8,412	563	5,136
Decrease (increase) in other assets	3,853	3,686	(1,101)
Payments received on direct financing lease and notes receivable	2,539	2,250	1,994
Net cash used in investing activities	(122,188)	(409,281)	(196,887)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	389,000	807,000	250,000
Scheduled principal repayments	(5,000)	0	0
Other principal repayments of debt	(393,000)	(543,000)	(255,000)
Payment of debt issuance and other refinancing and related costs	(68)	(5,727)	0
Payment of lease obligations	(11,789)	(6,468)	0
Contingent consideration for acquisition of businesses	(5,073)	0	0
Proceeds from exercise of stock options	2,638	7,700	12,450
Purchase and retirement of common stock	(4,006)	(9,454)	(4,036)
Income tax benefit of equity compensation	1,479	525	665
Decrease (increase) in restricted cash for dividends	550	500	(251)
Dividends paid	(255,496)	(250,695)	(234,048)
Net cash provided by (used in) financing activities	(280,765)	381	(230,220)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(27,580)	(9,102)	(3,526)
CASH AND CASH EQUIVALENTS, beginning of year	65,291	74,393	77,919
CASH AND CASH EQUIVALENTS, end of year	37,711	65,291	74,393
Cash paid during the period for:
Interest (net of amounts capitalized of $552, $5,478, and $2,525 in 2016, 2015, and 2014, respectively)	55,966	36,992	39,928
Income taxes paid (refunded), net	$ (2,137)	$ 9,966	$ 19,717