Employee Benefit Plans Summary of Pension Plan and Postretirement Plan Net Periodic Benefit Cost (Details) (USD $) In Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Pension Plan [Member]
Define Benefit Plan Disclosure [Line Items]
Service cost	$ 15	[1]	$ 26	[1]	$ 45	[1]	$ 78	[1]
Interest cost	853		842		2,559		2,526
Expected return on plan assets	(837)		(802)		(2,511)		(2,406)
Net amortization and deferral	72		119		216		357
Net periodic benefit cost	103		185		309		555
Postretirement Plan [Member]
Define Benefit Plan Disclosure [Line Items]
Service cost	50		48		151		146
Interest cost	107		110		321		330
Expected return on plan assets	(1)		(1)		(3)		(3)
Net accretion and deferral	(91)		(91)		(273)		(273)
Net periodic benefit cost	$ 65		$ 66		$ 196		$ 200

[1] (1)The Pension Plan service cost recorded for the three and nine months ended September 30, 2011 and 2010, respectively, was related to administrative costs associated with the plan and not due to the accrual of additional participant benefits.