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	$ 193,389	$ 241,840	$ 158,405
Adjustments to reconcile net income to net cash flows from operating activities:
(Income) from discontinued operations, net of income taxes	0	(50,924)	(23,794)
Depreciation	115,103	111,214	107,303
Amortization	79,579	81,050	73,234
Provision for share based compensation	25,388	22,925	15,574
Deferred income tax (benefit) expense	(30,211)	8,930	(26,632)
Amortization of deferred financing costs	48,342	21,945	31,636
Increase in acquisition contingent consideration	1,099	234	0
(Gain) loss on disposal of equipment	(13,654)	438	(316)
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable	15,984	(9,257)	13,169
Other assets	28,065	(7,675)	(52,479)
Accounts payable	(15,799)	21,345	6,771
Accrued wages	6,378	3,735	1,859
Interest payable	(1,868)	(8,083)	57,439
Income tax payable	21,650	(25,085)	5,824
Accrued expenses and other liabilities	(45,170)	(1,864)	41,498
Net cash flows from continuing operating activities	428,275	410,768	409,491
Net cash flows from discontinued operating activities	0	7,222	53,232
Total net cash flows from operating activities	428,275	417,990	462,723
CASH FLOWS FROM INVESTING ACTIVITIES:
Business acquisitions, net of cash acquired of $35, $204 and $0	(19,920)	(94,376)	(398,060)
Purchase of property and equipment	(126,581)	(136,810)	(130,318)
Proceeds from sale of property and equipment	38,518	303	3,176
Other	(280)	(1,550)	826
Net cash flows from continuing investing activities	(108,263)	(232,433)	(524,376)
Net cash flows from discontinued investing activities	0	275,815	(20,530)
Total net cash flows from investing activities.	(108,263)	43,382	(544,906)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of notes	400,000	0	1,000,000
Proceeds from term loan facility	1,780,000	250,000	350,000
Payments on notes and term loan facilities	(2,405,078)	(323,661)	(1,401,560)
Proceeds from issuance of long-term revolving credit obligations	119,000	139,000	382,765
Payments on long-term revolving credit obligations	(85,000)	(324,000)	(197,765)
Dividends paid	(74,706)	(75,161)	(75,702)
Debt issuance costs	(30,654)	(4,848)	(27,330)
Debt redemption premiums paid on senior and subordinated notes	0	0	(61,708)
Repurchases of common stock	(21,961)	(59,957)	0
Proceeds from stock options exercised and ESPP shares issued including excess tax benefits	6,488	10,384	6,273
Net cash flows from continuing financing activities	(311,911)	(388,243)	(25,027)
Net cash flows from discontinued financing activities	0	0	0
Total net cash flows from financing activities	(311,911)	(388,243)	(25,027)
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(7,380)	(5,852)	(7,770)
NET CHANGE IN CASH AND CASH EQUIVALENTS	721	67,277	(114,980)
CASH AND CASH EQUIVALENTS, Beginning of period	182,338	115,061	230,041
CASH AND CASH EQUIVALENTS, End of period	$ 183,059	$ 182,338	$ 115,061