Stockholders' Equity (Stock Rollforward) (Details)	9 Months Ended
	Sep. 30, 2018 shares
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	20,119,194
Treasury stock, end of period	608,379
Common Stock
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	14,098
Common stock, end of period	20,119,194
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	30,808
Cancellation of restricted common shares	1,961
Grant of common shares	(16,544)
Changes related to deferred compensation plan for Boards of Directors:
Purchase of treasury stock	4,646
Disbursed out of treasury stock	(2,089)
Common shares issued under compensation plan for Boards of Directors	(3,088)
Common shares issued under employee stock purchase plan	(5,186)
Treasury stock, end of period	609,250
ASB Financial Corp. [Member] | Common Stock
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	(103,605)