Goodwill and Intangible Assets - Finite-lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-lived Intangible Assets, Gross [Roll Forward]
Intangible assets, January 1	$ 34,362	$ 7,602
Additions	0	26,760
Total intangible assets, end of year	34,362	34,362
Accumulated Amortization [Roll Forward]
Accumulated amortization, January 1	(11,933)	(7,515)
Current year amortization	(7,287)	(4,418)
Total accumulated amortization	(19,220)	(11,933)
Net intangible assets, end of year	$ 15,142	$ 22,429