Pension and Other Post-Retirement Benefits (Components of Pension Expense and Other Post-Retirement Benefit Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0
Interest cost	20,518	18,447	21,505
Expected return on plan assets	(24,157)	(23,900)	(26,939)
Amortization of prior service cost	0	32	44
Amortization of actuarial loss	7,378	10,627	8,585
Total	3,739	5,206	3,195
Other Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	49	98	163
Expected return on plan assets	0	0	0
Amortization of prior service cost	(103)	0	0
Amortization of actuarial loss	34	8	86
Total	$ (20)	$ 106	$ 249