Income Taxes - Provision (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income before income taxes	$ 6,750	$ 80,275	$ 72,076	$ 146,847
Income tax provision	4,213	18,282	28,512	42,968
Net income	$ 2,537	$ 61,993	$ 43,564	$ 103,879
Income tax provision as a percentage of income before income taxes	62.40%	22.80%	39.60%	29.30%