Derivatives - Additional Information (Details)		3 Months Ended
	Jul. 28, 2017 USD ($) InterestRateSwap	Mar. 31, 2017	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Lock in period for interest rates		45 days
Long-term debt			$ 43,790,000	$ 44,892,000
Subsequent Event | Wells Fargo Bank
Derivative [Line Items]
Notional amount	$ 100,000,000
Subordinated Debentures
Derivative [Line Items]
Long-term debt			30,930,000
Interest Rate Contracts with Corporate Customers
Derivative [Line Items]
Notional amount			92,142,000	22,243,000
Offsetting Interest Rate Contracts with Other Financial Institutions
Derivative [Line Items]
Notional amount			92,142,000	22,243,000
Interest Rate Swaps
Derivative [Line Items]
Fair value on swap			1,350,000	586,000
Interest Rate Swaps | Subsequent Event | Wells Fargo Bank
Derivative [Line Items]
Number of derivative instruments | InterestRateSwap	3
Interest Rate Swaps | Subordinated Debentures
Derivative [Line Items]
Notional amount			30,000,000
Fair value on swap			0
Interest Rate Swaps Three | Subsequent Event | Wells Fargo Bank
Derivative [Line Items]
Notional amount	$ 30,000,000
Derivative notional amount maturity period	3 years
Interest Rate Swaps Four | Subsequent Event | Wells Fargo Bank
Derivative [Line Items]
Notional amount	$ 35,000,000
Derivative notional amount maturity period	4 years
Interest Rate Swaps Five | Subsequent Event | Wells Fargo Bank
Derivative [Line Items]
Notional amount	$ 35,000,000
Derivative notional amount maturity period	5 years
Commitments to Fund Fixed-Rate Mortgage Loans
Derivative [Line Items]
Notional amount			546,520,000	532,920,000
Commitments to Sell Residential Mortgage Loans
Derivative [Line Items]
Notional amount			$ 751,500,000	$ 829,000,000