Stock- Based Compensation (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 31, 2014
Stock-Based Compensation [Abstract]
Shares available for future grant under the plan	889,735
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized in connection with the issuance of Deferred Stock Units (in US dollars)	$ 394,000	$ 394,000	$ 300,000
Deferred Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Granted Per Director (in shares)				212
Expense recognized in connection with the issuance of Deferred Stock Units (in US dollars)				394,000
Expense per grant recognized in connection with the issuance of Deferred Stock Units (in US dollars)				$ 56,250
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Number	5,005