Goodwill and Core Deposit Intangibles - CDI Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gross amount of CDI:
Balance, beginning of year	$ 10,782	$ 7,876	$ 7,876
Additions due to acquisitions	4,320	2,906	0
Balance, end of year	15,102	10,782	7,876
Accumulated Amortization
Balance, beginning of year	(3,612)	(2,262)	(1,248)
Amortization	(2,039)	(1,350)	(1,014)
Balance, end of year	(5,651)	(3,612)	(2,262)
Net CDI, end of year	$ 9,451	$ 7,170	$ 5,614