Components of Net Periodic Benefit Cost (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Benefits Plan Estimated Future Employer Contributions In Next Fiscal Year			$ 1,800,000
Defined Benefit Plan, Expected Future Benefit Payments, Next Rolling Twelve Months			1,100,000
Defined Contribution Plan Employer Accrued Discretionary Contribution Amount	359,000	350,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made by employer	0
Post-Retirement Health Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefits Plan Estimated Future Employer Contributions In Next Fiscal Year			247,000
Contributions made by employer	$ 57,000