Goodwill and Core Deposit Intangibles - Goodwill Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance, beginning of year	$ 50,832	$ 22,950
Goodwill acquired during the year	51,658	27,882
Impairment losses	0	0
Balance, end of year	102,490	50,832
Accumulated impairment losses at end of year	$ 0	$ 0