Investment in Affordable Housing Projects (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Investment	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Schedule Of Equity Method Investments [Line Items]
Number of limited liability partnerships with investments | Investment			7
Year in which investments are expected to be paid			2021
Tax credits and other benefits recognized			$ 252,000	$ 270,000
Losses from investments in affordable housing projects	$ 63,000	$ 65,000	143,000	$ 87,000
Other Assets [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in affordable housing projects	4,600,000		4,600,000		$ 3,800,000
Other Liabilities [Member]
Schedule Of Equity Method Investments [Line Items]
Capital call for investments in affordable housing projects	$ 1,200,000		$ 1,200,000		$ 1,200,000