Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 575	$ 550	$ 1,725	$ 1,649
Interest Cost	617	604	1,851	1,812
Expected Return on Assets	(724)	(615)	(2,171)	(1,844)
Amortization of Unrecognized Losses	408	387	1,224	1,162
Amortization of Unrecognized Prior Service Cost	2	2	7	7
Amortization of Transition Obligation
Net Periodic Benefit Cost	878	928	2,636	2,786
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service Cost	334	446	1,003	1,338
Interest Cost	399	467	1,196	1,401
Expected Return on Assets	(406)	(314)	(1,217)	(943)
Amortization of Unrecognized Losses	516	441	1,549	1,324
Amortization of Unrecognized Prior Service Cost	(432)		(1,296)
Amortization of Transition Obligation		33		101
Net Periodic Benefit Cost	$ 411	$ 1,073	$ 1,235	$ 3,221