Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 50,047	$ 46,307
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	36,257	42,059
Amortization of debt issuance costs and other non-cash interest	783	792
Asset impairments	259
Deferred income taxes	1,867	875
Non-cash revenue and other income	(5,371)	(496)
Income tax benefit of equity compensation		(16)
Non-cash equity compensation	4,086	3,781
Other expenses and non-cash items	831	787
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	22,002	39,014
Accounts payable, accrued expenses and other liabilities	(19,785)	(13,311)
Income taxes payable	515	517
Net cash provided by operating activities	91,491	120,309
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(6,417)	(7,793)
Expenditures for other capital improvements	(8,173)	(6,290)
Acquisition of businesses, net of cash acquired	(7,062)	(1,780)
Decrease in restricted cash		240
Proceeds from sale of assets	77	139
Decrease in other assets	1,561	661
Payments received on direct financing lease and notes receivable	684	606
Net cash used in investing activities	(19,330)	(14,217)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	60,000	55,000
Scheduled principal repayments	(2,500)	(1,250)
Other principal repayments of debt	(72,000)	(100,000)
Payment of debt issuance and other refinancing and related costs	(65)	(66)
Payment of lease obligations	(553)	(3,260)
Dividends paid	(51,462)	(65,108)
Income tax benefit of equity compensation		16
Purchase and retirement of common stock	(5,089)	(3,528)
Decrease in restricted cash for dividends		550
Proceeds from exercise of stock options	4,961	1,079
Net cash used in financing activities	(66,708)	(116,567)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	5,453	(10,475)
CASH AND CASH EQUIVALENTS, beginning of period	37,711	65,291
CASH AND CASH EQUIVALENTS, end of period	43,164	54,816
Cash paid during the period for:
Interest (net of amount capitalized of $0 and $60 in 2017 and 2016, respectively)	$ 10,899	3,602
Income taxes refunded, net		$ (12,028)