Income Tax Expense (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Partnership	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) Partnership
Income Tax Expense [Abstract]
Number of investments in partnerships | Partnership			4		4
Investment amount in partnerships	$ 581,000		$ 581,000		$ 700,000
Investment Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Investment tax credits	740,000		$ 740,000
Tax credits recognition period			5 years 3 months
Tax credits recognized as reduction of tax expense amount	36,000	$ 50,000	$ 106,000	$ 149,000
Amortization of investment in other expenses	$ 39,000	$ 65,000	$ 119,000	$ 194,000