Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Short-term Debt [Line Items]
Total short-term borrowings	$ 150,580	$ 243,351
FHLB Fixed Rate Credit Advances with interest rates ranging from 1.41% to 1.42%, and 0.51% to 0.74%, for 2017 and 2016, respectively
Short-term Debt [Line Items]
FHLB Fixed Rate Credit Advances, Current	125,000	225,000
Maturity Overnight
Short-term Debt [Line Items]
Repurchase agreements at an average period-end rate of 0.19% and 0.16% for 2017 and 2016, respectively	$ 25,580	$ 18,351
Debt Instrument, Interest Rates [Abstract]
Average rate (in percent)	0.19%	0.16%
Minimum | FHLB Fixed Rate Credit Advances with interest rates ranging from 1.41% to 1.42%, and 0.51% to 0.74%, for 2017 and 2016, respectively
Debt Instrument, Interest Rates [Abstract]
Average rate (in percent)	1.41%	0.51%
Maximum | FHLB Fixed Rate Credit Advances with interest rates ranging from 1.41% to 1.42%, and 0.51% to 0.74%, for 2017 and 2016, respectively
Debt Instrument, Interest Rates [Abstract]
Average rate (in percent)	1.42%	0.74%