Fair Value Measurements - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Details) - Fair Value, Measurements, Nonrecurring - USD ($)		Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on nonrecurring basis		$ 0	$ 0
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	21,441,000	6,759,000
Other real estate owned	[1]	2,826,000	444,000
Mortgage servicing rights	[1]	1,197,000	178,000
Total Assets	[1]	25,464,000	7,381,000
Level 1
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 2
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 3
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	21,441,000	6,759,000
Other real estate owned	[1]	2,826,000	444,000
Mortgage servicing rights	[1]	1,197,000	178,000
Total Assets	[1]	$ 25,464,000	$ 7,381,000

[1] This table presents only the nonrecurring items that are recorded at fair value in our financial statements.