Income Taxes - Rollforward of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of unrecognized tax benefits
Balance at beginning of year	$ 663	$ 3,700	$ 0
Additions based on tax provisions related to the current year	0	0	3,700
Additions for tax positions of prior years	0	0	0
Reductions for tax positions of prior years	0	(3,037)	0
Settlements	0	0	0
Balance at end of year	$ 663	$ 663	$ 3,700