Goodwill and Intangible Assets - Finite-lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Finite-lived Intangible Assets, Gross [Roll Forward]
Intangible assets, January 1	$ 34,362	$ 34,362
Additions	0	0
Total intangible assets, end of period	34,362	34,362
Accumulated amortization, January 1
Accumulated amortization, January 1	(19,220)	(11,933)
Current year amortization	(1,270)	(1,822)
Total accumulated amortization	(20,490)	(13,755)
Net intangible assets, end of period	$ 13,872	$ 20,607