Consolidated Statement of Shareholders' Equity - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Total	Common Shares	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Restricted Shares	Restricted Shares Common Shares	Restricted Shares Treasury Stock	ASB Financial Corp. [Member] Common Shares
Balance, December 31, 2017 at Dec. 31, 2017	$ 458,592	$ 345,412	$ 134,362	$ (5,215)	$ (15,967)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amounts reclassified out of retained earnings, net of tax, per ASU 2014-09 | Accounting Standards Update 2014-09 [Member]			(3,055)
Net income	19,633		19,633
Other comprehensive income, net of tax	5,020
Other comprehensive income, net of tax	(7,368)			(12,388)
Cash dividends declared	(10,237)		(10,237)
Exercise of stock appreciation rights	0	(2)			2
Reissuance of treasury stock for deferred compensation plan for Boards of Directors						$ 0	$ (2,346)	$ 2,346
Reissuance of treasury stock for deferred compensation plan for Boards of Directors	46				46
Repurchase of treasury stock in connection with employee incentive plan and under compensation plan for Boards of Directors	(1,143)				(1,143)
Common shares issued under dividend reinvestment plan	338	338
Common shares issued under compensation plan for Boards of Directors	184	(63)			121
Common shares issued under employee stock purchase plan	94	(31)			63
Share-based Compensation	1,357	1,357
Issuance of common shares related to acquisition of ASB Financial Corp.	40,898								$ 40,898
Balance, June 30, 2018 at Jun. 30, 2018	$ 499,339	$ 385,751	$ 145,723	$ (17,603)	$ (14,532)