Fair Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	$ 4,200,000	$ 4,000,000.0
Discount percentage applied to real estate appraised values	15.00%
Discount percentage applied to lot development appraised values	6.00%
Mortgage loan servicing rights	$ 10,070,000	10,178,000	$ 9,688,000	$ 9,266,000
Servicing Asset at Fair Value, Amount	5,800,000	1,200,000
Valuation Allowance for Impairment of Recognized Servicing Assets, Balance	825,000	232,000	630,000	$ 735,000
MSRs recorded at cost	4,300,000	9,000,000.0
Valuation Allowance for Impairment of Recognized Servicing Assets, Additions (Deductions) for Expenses (Recoveries)	593,000	(398,000)	(105,000)
Other real estate owned	$ 4,029,000	$ 4,303,000
Percent of OREO held at fair value	75.00%	85.00%
Estimated fair value of other real estate owned (OREO)	$ 3,000,000.0	$ 3,700,000
OREO devaluations	225,000	491,000	458,000
expense related to other repossessed assets	0	269,000	$ 0
Alternative Investment	20,411,000	17,065,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	8,500,000	6,100,000
Alternative Investment, income recognized	4,800,000	1,400,000
Nonrecurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	3,599,000	3,464,000
Servicing Asset at Fair Value, Amount	5,797,000	1,169,000
Fair Value, Inputs, Level 3 [Member] | Nonrecurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	3,599,000	3,464,000
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative Investment	$ 11,900,000	$ 11,000,000.0