Employee Benefit Plans Employee Benefit Plans and Components of Net Periodic Postretirement Benefit Cost (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions paid	$ 0	$ 0
Anticipated cash contributions to pension plan in remaining fiscal year	0
Pension and Other Postretirement Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	127	213
Interest cost	1,740	1,619
Expected return on assets	(2,095)	(2,320)
Amortization of prior service cost	71	81
Amortization of actuarial loss	345	485
Net periodic pension and postretirement benefit cost (credit)	$ 188	$ 78