Pension and Post-Retirement Benefit Costs (Components of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 250	$ 224	$ 754	$ 705
Interest cost	645	681	1,936	2,042
Expected return on plan assets	(623)	(570)	(1,867)	(1,709)
Amortization of prior service cost	74	74	223	223
Amortization of net loss	445	322	1,329	948
Net periodic benefit cost	791	731	2,375	2,209
Post-Retirement Healthcare
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	4	7	12
Interest cost	185	209	555	628
Amortization of transition obligation	0	28	0	85
Amortization of prior service cost	21	47	63	140
Amortization of net loss	44	28	132	84
Net periodic benefit cost	$ 252	$ 316	$ 757	$ 949