Financial Instruments with Off- Balance Sheet Risk (Details)	6 Months Ended
	Jun. 30, 2018 USD ($) contract	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 8,400,000		$ 4,600,000
Interest Rate Derivative Liabilities, at Fair Value	$ 5,100,000		3,200,000
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge	10 years
Reclassifications into Interest expense on cash flow hedge	$ 0
Reclassifications into interest expense on cash flow hedge, next twelve months	0
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	3,300,000	$ 0
Reclassifications into earnings on cash flow hedge	0
Fair Value of Interest Rate Swaps	$ 5,100,000		3,000,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held | contract	10
Derivative, Notional Amount	$ 67,000,000
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 388,900,000		$ 363,300,000
ASB Financial Corp. [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held | contract	3
Derivative, Notional Amount	$ 7,000,000
Peoples Bancorp Inc. [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held | contract	7