Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings from continuing operations before income taxes:
United States									$ 344,614	$ 408,757	$ 275,630
Foreign									61,767	60,458	62,637
Earnings from continuing operations before income taxes	$ 69,196	$ 131,698	$ 116,779	$ 88,708	$ 111,691	$ 139,900	$ 133,447	$ 84,177	406,381	469,215	338,267
Current tax expense (benefit) from continuing operations:
Federal									2,731	(1,836)	(230)
State									7,713	5,748	6,396
Foreign									6,411	5,272	7,163
Total									16,855	9,184	13,329
Deferred tax expense from continuing operations:
Federal									106,513	135,585	90,056
State									16,259	20,111	12,429
Foreign									2,114	(1,654)	2,228
Total									124,886	154,042	104,713
Provision for income taxes from continuing operations									$ 141,741	$ 163,226	$ 118,042