Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Current tax expense (benefit):
Income tax provision	$ 21,004	$ 16,575	$ 46,124	$ 85,555
Current income tax expense (benefit)			$ 47,000
Effective tax rate	24.80%	22.00%	22.60%	44.90%
Deferred tax expense (benefit):
Deferred income taxes			$ (2,337)	$ (200)
Deferred Income Tax Expense (Benefit), Excluding Discontinued Operations			$ 59,500
Effective tax rate	24.80%	22.00%	22.60%	44.90%