Derivatives - Additional Information (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) derivative_swap	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Derivatives, Fair Value [Line Items]
Threshold for collateral requirements	$ 250,000
Collateral posted	301,000	$ 216,000
Notional amount	$ 18,900,000	21,300,000
Number of instruments | derivative_swap	4
Derivative fee income	$ 0	0	$ 0
Commitments to originate loans held for sale	62,421,000	71,820,000
RML
Derivatives, Fair Value [Line Items]
Commitments to originate loans held for sale	62,400,000	$ 71,300,000
Variable to Fixed
Derivatives, Fair Value [Line Items]
Notional amount	$ 9,500,000
Number of instruments | derivative_swap	2
Fixed to Variable
Derivatives, Fair Value [Line Items]
Notional amount	$ 9,500,000
Number of instruments | derivative_swap	2