Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 159,207	$ 178,040	$ 219,919
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	156,501	147,129	166,746
Asset impairments	1,580	614
Amortization of debt issuance costs and other non-cash interest	3,419	3,222	3,147
Expenses associated with debt refinancing transactions	1,016
Deferred income taxes	(4,436)	921	(3,911)
Other expenses and non-cash items	7,909	4,267	5,265
Non-cash revenue and other income	(14,509)	(14,528)	(8,518)
Income tax benefit of equity compensation			(1,479)
Non-cash equity compensation	13,132	13,286	17,903
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	(19,470)	(13,913)	14,059
Accounts payable, accrued expenses and other liabilities	19,377	21,339	(39,403)
Income taxes payable	(846)	948	1,645
Net cash provided by operating activities	322,880	341,325	375,373
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(58,239)	(17,576)	(41,816)
Expenditures for other capital improvements	(63,438)	(56,168)	(51,647)
Acquisitions, net of cash acquired	(175,588)	(48,867)	(43,769)
Proceeds from sale of assets	12,911	970	8,412
(Increase) decrease in other assets	(6,703)	(3,605)	4,643
Payments received on direct financing lease and notes receivable		684	2,539
Net cash used in investing activities	(291,057)	(124,562)	(121,638)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt and borrowings from credit facility	809,831	475,500	389,000
Scheduled principal repayments	(7,816)	(10,000)	(5,000)
Other principal repayments of debt	(603,500)	(461,500)	(393,000)
Payment of debt issuance and other refinancing and related costs	(6,087)	(4,169)	(68)
Payment of lease obligations	(3,744)	(2,483)	(11,789)
Contingent consideration for acquisition of businesses	(1,500)		(5,073)
Proceeds from exercise of stock options	2,367	6,534	2,638
Proceeds from sale/leaseback	7,783
Purchase and retirement of common stock	(3,005)	(5,847)	(4,006)
Income tax benefit of equity compensation			1,479
Dividends paid	(204,198)	(200,326)	(255,496)
Net cash used in financing activities	(9,869)	(202,291)	(281,315)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	21,954	14,472	(27,580)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period	52,183	37,711	65,291
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period	74,137	52,183	37,711
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Debt assumed on acquisition of property	157,280
Cash paid during the period for:
Interest (net of amounts capitalized of $994, $0, and $552 in 2018, 2017, and 2016, respectively)	71,787	57,485	55,966
Income taxes paid (refunded), net	$ 13,303	$ 8,089	$ (2,137)