Goodwill and Other Intangible Assets - Carrying Value of Intangibles (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Gross carrying value, core deposit intangibles	$ 11,508	$ 11,508
Accumulated amortization, core deposit intangibles	(10,582)	(10,317)
Net carrying value, core deposit intangibles	926	1,191
Gross carrying value, goodwill	43,872	43,872
Accumulated amortization, goodwill	0	0
Net carrying value, goodwill	$ 43,872	$ 43,872	$ 43,872