Income Taxes Income Taxes Details 2 (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Current: United States									$ 154,128	$ 113,629	$ 94,502
Current: Foreign									12,187	12,084	9,270
Current: State									4,934	16,150	13,207
Total current income taxes									171,249	141,863	116,979
Deferred: United States									(314,389)	(19,496)	15,918
Deferred: Foreign									618	22,708	(878)
Deferred: State									(4,067)	4,278	3,008
Provision for deferred income taxes									(317,838)	7,490	18,048
Provision for income taxes	$ 113,759	$ (10,437)	$ (32,956)	$ 76,223	$ (72,872)	$ (27,422)	$ (16,746)	$ (32,313)	(146,589)	149,353	135,027
Income Taxes Paid									170,200	115,000	105,400
Proceeds from Income Tax Refunds									$ 3,400	$ 2,400	$ 1,900