Income Tax Expense (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) Partnership	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($) Partnership
Income Tax Expense [Abstract]
Investments in number of partnerships | Partnership	4		4
Investment amount in partnerships	$ 1,088,000	$ 1,088,000	$ 1,218,000
Tax Credit Carryforward [Line Items]
Investment tax credits	$ 1,143,000	1,143,000
Investment Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax credits recognition period	7 years
Tax credits recognized as reduction of tax expense amount	$ 49,000	$ 99,000