Income Taxes (Income Tax Expense) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2016	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 3,500,000	$ 700,000	$ 75,400,000	$ 41,100,000
State	400,000	(1,500,000)	8,500,000	5,800,000
Foreign	800,000	3,800,000	29,000,000	10,300,000
Total current income tax expense	4,700,000	3,000,000	112,900,000	57,200,000
Deferred:
Federal		(213,300,000)	42,800,000	28,900,000
State		(17,400,000)	3,500,000	2,400,000
Foreign	(400,000)	(600,000)	(3,500,000)	600,000
Total deferred income tax expense (benefit)	(400,000)	(231,300,000)	42,800,000	31,900,000
Total income tax (benefit) expense	$ 4,300,000	$ (228,300,000)	$ 155,700,000	$ 89,100,000