Retirement Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net pension cost included the following components:
Service cost-benefits earned during the period	$ 185	$ 170
Interest cost on projected benefit obligation	160	172
Amortization of net obligation at transition
Amortization of prior service cost	38	38
Recognized net actuarial loss	72	72
Net periodic pension cost	$ 455	$ 452