Financial Instruments with Off- Balance Sheet Risk (Details)	9 Months Ended
	Sep. 30, 2017 USD ($) contract	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 4,800,000		$ 5,000,000
Interest Rate Derivative Liabilities, at Fair Value	$ 3,900,000		3,200,000
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge	10 years
Maximum Length of Time Hedged in Cash Flow Hedge	13 months
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)	1,000,000	$ 0
Reclassifications into earnings on cash flow hedge	0
Fair Value of Interest Rate Swaps	$ 3,500,000		3,200,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held | contract	7
Derivative, Notional Amount	$ 60,000,000
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 334,200,000		$ 247,300,000