Components of Net Periodic Benefit Cost (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 510	$ 559	$ 1,530	$ 1,678
Interest cost	939	846	2,817	2,537
Expected return on plan assets	(948)	(827)	(2,845)	(2,482)
Amortization of transition obligation	0	0		0
Net amortization of prior service cost	(2)	(4)	(7)	(12)
Net amortization of net (gain) loss	190	523	569	1,568
Net Periodic Benefit Cost	689	1,097	2,064	3,289
Post-Retirement Health Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	13	17	40	51
Interest cost	44	43	131	130
Expected return on plan assets	0	0		0
Amortization of transition obligation	0	15		44
Net amortization of prior service cost	0	0		0
Net amortization of net (gain) loss	0	0	(1)	0
Net Periodic Benefit Cost	$ 57	$ 75	$ 170	$ 225