Fair Value (Fair Value Measurement Non-recurring) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Benefit to provision for loan losses	$ (4,903)	$ (5,201)	$ (4,918)	$ (1,635)	$ (9,681)	$ (5,238)	$ (4,831)	$ (4,263)	$ (16,657)	$ (24,013)	$ (15,563)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0				0				0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	26,748				52,577				26,748	52,577
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0				67,224				0	67,224
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	36,464				25,509				36,464	25,509
Loans held for sale	26,748				119,801				26,748	119,801
Other real estate owned	6,914				6,153				6,914	6,153
Premises, furniture and equipment held for sale	2,967				7,258				2,967	7,258
Nonrecurring Basis | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	2,450				1,307				2,450	1,307
Loans held for sale	(980)				(1,870)				(980)	(1,870)
Other real estate owned	947				2,647				947	2,647
Premises, furniture and equipment held for sale	735				59				735	59
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Loans held for sale	0				0				0	0
Other real estate owned	0				0				0	0
Premises, furniture and equipment held for sale	0				0				0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Loans held for sale	26,748				52,577				26,748	52,577
Other real estate owned	0				0				0	0
Premises, furniture and equipment held for sale	0				0				0	0
Nonrecurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	36,464				25,509				36,464	25,509
Loans held for sale	0				67,224				0	67,224
Other real estate owned	6,914				6,153				6,914	6,153
Premises, furniture and equipment held for sale	2,967				7,258				2,967	7,258
Benefit to provision for loan losses										953
Nonrecurring Basis | Commercial Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	5,621				7,143				5,621	7,143
Nonrecurring Basis | Commercial Servicing Rights | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	911				58				911	58
Nonrecurring Basis | Commercial Servicing Rights | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0				0				0	0
Nonrecurring Basis | Commercial Servicing Rights | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	0				0				0	0
Nonrecurring Basis | Commercial Servicing Rights | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights	5,621				7,143				5,621	7,143
Nonrecurring Basis | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	15,173				12,932				15,173	12,932
Nonrecurring Basis | Commercial | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,114				660				1,114	660
Nonrecurring Basis | Commercial | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Commercial | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Commercial | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	15,173				12,932				15,173	12,932
Nonrecurring Basis | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	4,592				405				4,592	405
Nonrecurring Basis | Commercial Real Estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	72				72				72	72
Nonrecurring Basis | Commercial Real Estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Commercial Real Estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Commercial Real Estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	4,592				405				4,592	405
Nonrecurring Basis | Agricultural and Agricultural Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	12,623				11,070				12,623	11,070
Nonrecurring Basis | Agricultural and Agricultural Real Estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,254				575				1,254	575
Nonrecurring Basis | Agricultural and Agricultural Real Estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Agricultural and Agricultural Real Estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Agricultural and Agricultural Real Estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	12,623				11,070				12,623	11,070
Nonrecurring Basis | Residential Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	3,088				478				3,088	478
Nonrecurring Basis | Residential Real Estate | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	10				0				10	0
Nonrecurring Basis | Residential Real Estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Residential Real Estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Residential Real Estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	3,088				478				3,088	478
Nonrecurring Basis | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	988				624				988	624
Nonrecurring Basis | Consumer | (Gains)/Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Consumer | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Consumer | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0				0				0	0
Nonrecurring Basis | Consumer | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	$ 988				$ 624				$ 988	$ 624