Other Assets Other Assets Tax Credit Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017
Tax Credit Carryforward [Line Items]
Investment in limited partnerships	$ 4,261,000	$ 3,963,000
Investment Tax Credit Impairment Cost	2,784,000	3,691,000	$ 0
Investment in Community Development Entities	6,591,000	7,106,000
Mitchell Street Apartments \| Historic Rehabilitation Tax Credits
Tax Credit Carryforward [Line Items]
Investment in limited partnerships	570,000	563,000
Capital Contributions	4,900,000
Investment Tax Credit Impairment Cost	2,300,000
Gain on Sale of Tax Credits, Before Tax	210,000
Tax Credit Benefits Recognized	$ 3,000,000
Kenosha \| Historic Rehabilitation Tax Credits
Tax Credit Carryforward [Line Items]
Investment in limited partnerships				$ 417,000
Estimated Capital Contributions				$ 2,100,000
Rimrock Road \| New Market Tax Credits
Tax Credit Carryforward [Line Items]
New Market Tax Credit Benefit, Period of Recognition	7 years
Federal New Market Tax Credits Not Yet Recognized	$ 1,400,000
Tax Credit Benefits Recognized	450,000	375,000
BOC Investment \| Historic Rehabilitation Tax Credits
Tax Credit Carryforward [Line Items]
Investment in limited partnerships	$ 174,000
Capital Contributions		2,800,000
Investment Tax Credit Impairment Cost		3,300,000
Tax Credit Benefits Recognized		$ 3,800,000