Goodwill and Intangible Assets Reconciliation of purchase price to goodwill recorded (Details) - USD ($)		3 Months Ended
	Sep. 08, 2016	Sep. 30, 2017	Dec. 31, 2017	Aug. 14, 2015
First Clover Leaf [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Business Combination, Purchase Price	$ 8,741,000
Fair value of securities	109,174,000
Fair value of OREO	1,987,000
Fair value of premises and equipment	(11,581,000)
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans	438,265,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits	536,686,000
Fair value of FHLB advances	15,113,000
Fair value of subordinated debentures	(3,269,000)
Business Combination, Net Fair Value Adjustments	10,402,000
Goodwill Provisionally Recorded		$ 16,800,000
Goodwill, Acquired During Period	19,143,000	19,143,000
Measurement Period Adjustment to Other Liabilities		2,000,000
Measurement Period Adjustment to Other Assets		$ 300,000
OldNationalBankBranches [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Fair value of premises and equipment				$ (4,422,000)
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans				152,397,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment			$ 4,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits				453,647,000
Fair Value Adjustments [Member] | First Clover Leaf [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Fair value of securities	737,000
Fair value of loans	3,475,000
Fair value of OREO	754,000
Fair value of premises and equipment	(1,963,000)
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans	10,403,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits	1,994,000
Fair value of FHLB advances	113,000
Fair value of subordinated debentures	(731,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	(4,660,000)
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets, Net	10,683,000
Goodwill, Acquired During Period	$ 7,758,000
Fair Value Adjustments [Member] | OldNationalBankBranches [Member]
Reconciliation of purchase price to goodwill recorded [Line Items]
Fair value of premises and equipment				125,000
Business Combination, Recognized Identifiable Assets and Liabilities Assumed, Loans				(3,377,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits				$ 837,000