Fair Value Measurements - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on nonrecurring basis	$ 0	$ 0
Fair Value, Measurements, Nonrecurring
ASSETS
Loans held for sale	1,802,000	0
Impaired loans	10,329,000	9,373,000
Other real estate owned	396,000	158,000
Mortgage servicing rights	4,098,000	3,396,000
Total Assets	16,625,000	12,927,000
Fair Value, Measurements, Nonrecurring | Level 1
ASSETS
Loans held for sale	0	0
Impaired loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Total Assets	0	0
Fair Value, Measurements, Nonrecurring | Level 2
ASSETS
Loans held for sale	0	0
Impaired loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Total Assets	0	0
Fair Value, Measurements, Nonrecurring | Level 3
ASSETS
Loans held for sale	1,802,000	0
Impaired loans	10,329,000	9,373,000
Other real estate owned	396,000	158,000
Mortgage servicing rights	4,098,000	3,396,000
Total Assets	$ 16,625,000	$ 12,927,000