Commitments and Contingencies - Narrative (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) location $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Lease commitments
Rent expense	$ 5,800	$ 4,900	$ 5,100
Number of locations subleased | location	2
Future minimum sublease payments	$ 1,100
Future minimum lease payments	$ 33,351
Federal Reserve Bank stock, shares | shares	81,924
Federal Reserve Bank stock, value	$ 4,100
Federal Reserve Bank stock, par value | $ / shares	$ 50
Investment held as a percentage of total subscription amount due	50.00%
Percentage of investment that may be callable by the Federal Reserve	50.00%
Federal Reserve Bank stock, remaining membership subscription obligation	$ 4,100
Director
Lease commitments
Rent expense	2,100	$ 2,100	$ 2,100
Future minimum lease payments	$ 200