Acquisitions and Preliminary Purchase Price Allocation Acquisitions and Preliminary Purchase Price Allocation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
Dec. 31, 2018	Dec. 07, 2018
Farmers Deposit Bancorp, Inc.
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business Acquisition, Share Price		$ 1,174.14
Payments to Acquire Businesses, Gross	$ 24,900
Premium on Time Deposits		$ 100
Core deposit intangible		$ 3,334
Poage Bankshares, Inc.
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	1.1
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned		$ 82,600
Business Acquisition, Share Price		$ 24.22
Payments to Acquire Businesses, Gross	$ 83,936
Premium on Time Deposits		$ 1,700
Core deposit intangible		8,054
Poage and Farmers
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 108,836
Premium on Time Deposits Amortization Period	5 years
Core deposit intangible		$ 11,388
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years

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