Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Taxes
Pre-tax income	$ 19,136	$ 4,058	$ 34,817	$ 7,545
Cumulative years of pretax income in the U.S. federal tax jurisdiction			3 years
Deferred tax asset	42,256		$ 42,256
Effective Income Tax Rate Reconciliation, Percent			(120.90%)	6.00%
Income tax benefit relating to release of valuation allowance	$ 42,700