Business Combinations, Goodwill and Intangible Assets (Fair Value of Assets and Liabilities Acquired) (Details) - USD ($) $ in Thousands						12 Months Ended
	Oct. 15, 2018	Oct. 14, 2018	May 18, 2018	Mar. 01, 2016	Feb. 29, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consideration
Cash Consideration						$ 17,566	$ 0	$ 0
Total Cash Received from First Financial						42,700	0	0
Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:
Goodwill						$ 103,681	$ 54,058	$ 54,058	$ 20,536
First Security
Consideration
Cash for Options and Fractional Shares	$ 132	$ 124
Cash Consideration	31,039
Equity Instruments	64,898	$ 29,886
Fair Value of Total Consideration Transferred	96,069
Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:
Cash	13,605
Interest-bearing Time Deposits with Banks	250
Securities	109,580
Loans	390,106
Stock in FHLB of Indianapolis and Other Restricted Stock, at Cost	2,607
Premises, Furniture & Equipment	11,149
Other Real Estate	468
Intangible Assets	6,139
Company Owned Life Insurance	13,135
Accrued Interest Receivable and Other Assets	6,126
Deposits - Non-interest Bearing	(66,112)
Deposits - Interest Bearing	(358,285)
FHLB Advances and Other Borrowings	(73,275)
Accrued Interest Payable and Other Liabilities	(2,200)
Total Identifiable Net Assets	53,293
Goodwill	$ 42,776
Branch Acquisition
Consideration
Total Cash Received from First Financial			$ 41,944
Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:
Cash			756
Loans			116,305
Premises, Furniture & Equipment			5,666
Intangible Assets			3,475
Accrued Interest Receivable and Other Assets			780
Deposits - Non-interest Bearing			(39,607)
Deposits - Interest Bearing			(136,096)
Accrued Interest Payable and Other Liabilities			(70)
Total Identifiable Net Assets			(48,791)
Goodwill			$ 6,847
River Valley
Consideration
Cash for Options and Fractional Shares				$ 395	$ 395
Cash Consideration				24,975	$ 24,975
Equity Instruments				62,022
Fair Value of Total Consideration Transferred				87,392
Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:
Cash				17,877
Federal Funds Sold and Other Short-term Investments				6,477
Interest-bearing Time Deposits with Banks				992
Securities				132,396
Loans				317,760
Stock in FHLB of Indianapolis and Other Restricted Stock, at Cost				3,127
Premises, Furniture & Equipment				9,650
Other Real Estate				882
Intangible Assets				2,613
Company Owned Life Insurance				12,842
Accrued Interest Receivable and Other Assets				9,139
Deposits - Non-interest Bearing				(9,584)
Deposits - Interest Bearing				(395,862)
FHLB Advances and Other Borrowings				(49,910)
Accrued Interest Payable and Other Liabilities				(4,529)
Total Identifiable Net Assets				53,870
Goodwill				$ 33,522