Stockholders' Equity (Stock Rollforward) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) shares
Class of Stock [Line Items]
Issuance of common shares related to acquisition of ASB Financial Corp. | $	$ 40,898
Increase (Decrease) in Stock by Class [Roll Forward]
Common stock, beginning of period	18,952,385
Treasury stock, beginning of period	702,449
Changes related to stock-based compensation awards:
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(102)
Changes related to deferred compensation plan for Boards of Directors:
Common stock, end of period	20,114,405
Treasury stock, end of period	623,852
Common Shares
Increase (Decrease) in Stock by Class [Roll Forward]
Common stock, beginning of period	18,952,385
Changes related to stock-based compensation awards:
Cancellation of restricted common shares	0
Changes related to deferred compensation plan for Boards of Directors:
Common shares issued under dividend reinvestment plan	9,309
Common stock, end of period	20,114,405
Treasury Stock
Increase (Decrease) in Stock by Class [Roll Forward]
Treasury stock, beginning of period	702,449
Changes related to stock-based compensation awards:
Release of restricted common shares	29,045
Cancellation of restricted common shares	1,235
Grant of common shares	(15,112)
Changes related to deferred compensation plan for Boards of Directors:
Purchase of treasury stock	2,975
Disbursed out of treasury stock	(2,089)
Common shares issued under compensation plan for Boards of Directors	(1,589)
Common shares issued under employee stock purchase plan	2,707
Treasury stock, end of period	623,852
ASB Financial Corp. [Member] | Common Shares
Changes related to deferred compensation plan for Boards of Directors:
Issuance of common shares related to the acquisition of ASB Financial Corp.	1,152,711
Restricted Shares | Treasury Stock
Changes related to stock-based compensation awards:
Grant of common shares	(90,253)
Common Shares | ASB Financial Corp. [Member]
Class of Stock [Line Items]
Issuance of common shares related to acquisition of ASB Financial Corp. | $	$ 40,898