Quarterly Financial Data Quarterly Financial Data Level 4 (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																7 Months Ended	12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data (Unaudited) [Abstract]
Revenue	$ 820,814		$ 778,786		$ 796,092		$ 794,482		$ 812,733		$ 731,346		$ 773,242		$ 777,710		$ 17,900	$ 3,190,174	$ 3,095,031	$ 3,031,137
Costs and expenses	(610,551)		(612,616)		(607,965)		(598,720)		(600,487)		(581,570)		(589,724)		(600,471)			(2,429,852)	(2,372,252)	(2,354,287)
Gross profits	210,263		166,170		188,127		195,762		212,246		149,776		183,518		177,239			760,322	722,779	676,850
Operating income	172,710		132,303		161,954		163,692		177,999		109,351		143,902		139,891			630,659	571,143	513,323
Income from continuing operations before income taxes	126,012	[1]	86,036	[1]	119,315	[1]	110,369	[1]	133,636	[1]	66,578	[1]	101,518	[1]	98,526	[1]		441,732	400,258	326,658
Provision for income taxes	67,224		(17,043)		(16,034)		(28,321)		113,759		(10,437)		(32,956)		76,223			(5,826)	(146,589)	149,353
Net income	193,236		68,993		103,281		82,048		247,395		56,141		68,562		174,749		$ 1,700	447,558	546,847	177,305
Net income attributable to noncontrolling interests	(190)		(58)		(42)		(60)		(79)		23		(81)		(47)			(350)	(184)	(267)
Net income attributable to common stockholders	$ 193,046		$ 68,935		$ 103,239		$ 81,988		$ 247,316		$ 56,164		$ 68,481		$ 174,702			$ 447,208	$ 546,663	$ 177,038
Basic — EPS	$ 1.07	[2]	$ 0.38	[2]	$ 0.57	[2]	$ 0.44	[2]	$ 1.32	[2]	$ 0.30	[2]	$ 0.37	[2]	$ 0.93	[2]		$ 2.45	$ 2.91	$ 0.92
Earnings per share, diluted	$ 1.04	[2]	$ 0.37	[2]	$ 0.55	[2]	$ 0.43	[2]	$ 1.29	[2]	$ 0.29	[2]	$ 0.36	[2]	$ 0.91	[2]		$ 2.39	$ 2.84	$ 0.90

[1] Includes Gains (losses) on divestitures and impairment charges, net, as described in Note 15.

[2] Net income per share is computed independently for each of the quarters presented. Therefore, the sum of the quarters’ net income per share may not equal the total computed for the year.