Business Combinations, Goodwill and Intangible Assets (Narrative) (Details) $ / shares in Units, $ in Thousands						1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 15, 2018 USD ($) office shares	Oct. 14, 2018 USD ($) $ / shares	May 18, 2018 USD ($) office	Mar. 01, 2016 USD ($) office shares	Feb. 29, 2016 USD ($) $ / shares	Jan. 31, 2019 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2016	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Assets								$ 3,929,090		$ 3,929,090	$ 3,144,360	$ 2,955,994
Equity								458,640		458,640	364,571	330,267	$ 252,348
Goodwill								103,681		103,681	54,058	54,058	$ 20,536
Cash consideration										17,566	0	0
Amortization of expense intangible assets										1,752	942	1,062
Core Banking
Business Acquisition [Line Items]
Goodwill								102,349		102,349	52,726	52,726
Insurance
Business Acquisition [Line Items]
Goodwill								1,332		$ 1,332	$ 1,332	$ 1,332
First Security
Business Acquisition [Line Items]
Assets		$ 563,000
Equity		$ 58,300
First Security
Business Acquisition [Line Items]
Number of banking offices | office	11
Direct acquisition costs	$ 3,800
Goodwill	42,776
Intangible assets	$ 6,139
Shares of common stock issued for acquisition (in shares) | shares	1,988,000
Number of the Company's common stock for each share converted (in shares) | shares	0.7982
Cash portion, cash per share for common stock converted (USD per share) | $ / shares		$ 12.00
Equity Instruments	$ 64,898	$ 29,886
Cash for options and fractional shares	132	$ 124
Fair value of non-impaired loans and customers receivables acquired	382,400
Unpaid principal balance non-impaired loans and customers receivables acquired	385,400
Loans	390,106
Cash consideration	$ 31,039
First Security | Core Deposit Intangible
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful live	8 years
Branch Acquisition
Business Acquisition [Line Items]
Number of banking offices | office			5
Direct acquisition costs			$ 691
Goodwill			6,847
Intangible assets			3,475
Goodwill deductible for tax purposes			6,800
Deposits			175,700
Loans			116,305
Premium paid on deposits			$ 7,400
Period to adjust premium paid on deposits			6 months
Loans put back after acquisition date								$ 1,300
Branch Acquisition | Subsequent Event
Business Acquisition [Line Items]
Premium paid on deposits						$ 100
Branch Acquisition | Core Deposit Intangible
Business Acquisition [Line Items]
Intangible assets			$ 3,500
Acquired finite-lived intangible assets, weighted average useful live			8 years
Branch Acquisition | INDIANA
Business Acquisition [Line Items]
Number of banking offices | office			5
Branch Acquisition | Columbus, Indiana
Business Acquisition [Line Items]
Number of banking offices | office			4
Branch Acquisition | Greensburg, Indiana
Business Acquisition [Line Items]
Number of banking offices | office			1
River Valley
Business Acquisition [Line Items]
Assets					$ 516,300
Equity					$ 56,600
Direct acquisition costs				$ 4,300
Goodwill				33,522
Intangible assets				$ 2,613
Shares of common stock issued for acquisition (in shares) | shares				1,942,000
Number of the Company's common stock for each share converted (in shares) | shares				0.770
Cash portion, cash per share for common stock converted (USD per share) | $ / shares					$ 9.90
Equity Instruments				$ 62,022
Cash for options and fractional shares				395	$ 395
Fair value of non-impaired loans and customers receivables acquired				309,000
Unpaid principal balance non-impaired loans and customers receivables acquired				316,400
Loans				317,760
Cash consideration				$ 24,975	$ 24,975
River Valley | Core Deposit Intangible
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful live									8 years
River Valley | INDIANA
Business Acquisition [Line Items]
Number of banking offices | office				14
River Valley | KENTUCKY
Business Acquisition [Line Items]
Number of banking offices | office				1
Insurance Agency | INDIANA | German American Insurance, Inc. | Affiliated Entity
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful live							7 years
Cash consideration							$ 209
Insurance Agency | INDIANA | German American Insurance, Inc. | Customer Relationships | Affiliated Entity
Business Acquisition [Line Items]
Intangible assets							$ 209
KSOP Shares | First Security
Business Acquisition [Line Items]
Cash portion, cash per share for common stock converted (USD per share) | $ / shares		$ 40.00
Equity Instruments		$ 1