Employee Benefit Plans Employee Benefit Plans and Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments			$ 3,080	$ 0
Contributions paid	$ 0	$ 0	0	0
Anticipated cash contributions to pension plan in remaining fiscal year	0		0
Pension and Other Postretirement Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	237	128	474	255
Interest cost	1,795	1,740	3,590	3,480
Expected return on assets	(2,317)	(2,095)	(4,634)	(4,190)
Amortization of prior service cost	94	70	188	141
Amortization of actuarial loss	929	345	1,857	690
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	3,080	0	3,080	0
Net periodic pension and postretirement benefit cost	$ 3,818	$ 188	$ 4,555	$ 376