Goodwill and Intangible Assets Reconciliation of purchase price to goodwill recorded (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Aug. 14, 2015
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans			$ 152,397
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		$ 4,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits			453,647
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets			1,174
OldNationalBankBranches [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Purchase Price		15,892
Business Combination, Net Fair Value Adjustments		(1,618)
Goodwill, Acquired During Period	$ 14,300	14,274
Illiana [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Purchase Price		2,807
Goodwill, Acquired During Period		980
Fair Value Adjustments [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans			(3,377)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits			837
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets			$ (259)
Fair Value Adjustments [Member] | OldNationalBankBranches [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans		3,377
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		125
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits		837
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		(6,216)
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets		259
Fair Value Adjustments [Member] | Illiana [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Net Fair Value Adjustments		$ (1,827)