Pension and Other Post Retirement Benefit Plans Pension and Other Post Retirement Benefit Plans - Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Pension Cost	$ 1,167	$ 301
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Pension Cost	1,167	301
Net gain (loss)	(1,242)	(9,933)
Actuarial gain (loss)	2,207	1,129
Amortization of prior service (cost) credit	(25)	(25)
Total Recognized in Other Comprehensive Income	(990)	8,779
Total Recognized in NPPC and OCI	$ 177	$ 9,080