Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 730	$ 644
Interest Cost	719	706
Expected Return on Plan Assets	(925)	(746)
Amortization of Prior Service Cost	(8)	(8)
Recognized Net Actuarial Loss	414	244
Net Periodic Benefit Cost	930	840
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	50	38
Interest Cost	115	126
Expected Return on Plan Assets	0	0
Amortization of Prior Service Cost	0	0
Recognized Net Actuarial Loss	49	29
Net Periodic Benefit Cost	$ 214	$ 193