Mortgage Servicing Rights - Mortgage Servicing Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of period	$ 1,654
Changes in fair value:
Carrying value, December 31	4,157	$ 1,654
Balance of loans serviced for others	$ 272,442	$ 125,446
MSR as a percentage of serviced loans	1.53%	1.32%
Mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of period	$ 1,654	$ 1,010
Addition to servicing asset	3,029	802
Changes in fair value:
Due to changes in model inputs of assumptions	(214)	29
Other	(312)	(187)
Carrying value, December 31	$ 4,157	$ 1,654