Pension and Postretirement Benefits (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
Defined Benefit Plan Disclosure [Line Items]
Minimum years of service to participate in the health and life insurance benefits as of January 1, 1995			14 years
Contribution to defined benefit pension plan			$ 0	$ 2,600
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	166
Interest cost	95	93	284	305
Expected return on plan assets	(214)	(205)	(640)	(604)
Amortization of net losses	90	74	270	307
Net periodic plan (benefit) cost	(29)	(38)	(86)	174
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	4	4	13	13
Expected return on plan assets	0	0	0	0
Amortization of net losses	5	4	15	11
Net periodic plan (benefit) cost	$ 9	$ 8	$ 28	$ 24