Pension - Periodic Benefit Cost (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Components of net periodic benefit cost:
Interest cost	$ 17	$ 21
Service cost	9	9
Expected return on plan assets	(27)	(24)
Amortization of prior service costs	2	2
Amortization of actuarial loss	39	34
Net periodic benefit cost	$ 40	$ 42