Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill rollforward
Gross carrying Amount, beginning balance	$ 238,107	$ 238,158
Accumulated Impairment, beginning balance	123,199	123,199
Net Amount, beginning balance	114,908	114,959
Purchase price adjustments		(51)
Gross carrying Amount, ending balance	238,107	238,107
Accumulated Impairment, ending balance	123,199	123,199
Net Amount, ending balance	$ 114,908	$ 114,908