Income Taxes - Schedule of Net Deferred Tax liability (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 6,359	$ 6,264
Amortization of core deposit intangible	832	759
Deferred compensation	3,711	6,158
Unrealized loss on available-for-sale debt securities	3,830	988
Other	5,501	3,599
Subtotal	20,233	17,768
Deferred tax liabilities:
FHLB stock dividends	(550)	(550)
Depreciation	(4,344)	(4,115)
Cash flow hedges	(866)
Mortgage servicing rights	(24,274)	(19,830)
Other	(5,564)	(5,131)
Subtotal	(35,598)	(29,626)
Net deferred tax liability	$ (15,365)	$ (11,858)