Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	$ 78	$ 30	$ 46
Unrecognized actuarial losses	477	858	1,041
Total recognized in Accumulated Other Comprehensive Income	555	888	1,087
Income tax effect	(194)	(311)	(380)
Net amount recognized in Accumulated Other Comprehensive Income	$ 361	$ 577	$ 707