Employee Benefit Plans Summary of Pension Plan and Postretirement Plan Net Periodic Benefit Cost (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Pension Plan [Member]
Define Benefit Plan Disclosure [Line Items]
Service cost	$ 51	[1]	$ 39	[1]	$ 153	[1]	$ 117	[1]
Interest cost	772		806		2,316		2,418
Expected return on plan assets	(800)		(808)		(2,400)		(2,424)
Net amortization and deferral	596		420		1,788		1,260
Net periodic benefit cost	619		457		1,857		1,371
Postretirement Plan [Member]
Define Benefit Plan Disclosure [Line Items]
Service cost	57		53		171		159
Interest cost	81		87		243		261
Expected return on plan assets	0		(1)		0		(3)
Net accretion and deferral	(91)		(91)		(273)		(273)
Net periodic benefit cost	$ 47		$ 48		$ 141		$ 144

[1] The Pension Plan service cost recorded for the three and nine months ended September 30, 2013 and 2012, respectively, was related to administrative costs associated with the plan and was not due to the accrual of additional participant benefits.