Income Taxes - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
U.S. federal	$ 858	$ 1,086	$ 541
U.S. state	171	100	56
Non-U.S.	355	222	(12)
Total current	1,384	1,408	585
Deferred:
U.S. federal	11,324	8,913	(29,552)
U.S. state	573	(558)	(3,370)
Non-U.S.	(62)	78	252
Total deferred	11,835	8,433	(32,670)
Total income tax expense (benefit)	$ 13,219	$ 9,841	$ (32,085)