Employee Benefit Plans (Components of Net Periodic Postretirement Benefit Cost) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	$ 143	$ 148	$ 139
Interest cost	295	313	337
Amortization of prior service cost	161	161	161
Net periodic benefit cost (income)	$ 599	$ 622	$ 637