Employee Benefit Plans Employee Benefit Plans and Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 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	250		127	724	382
Interest cost	1,722		1,740	5,312	5,220
Expected return on assets	(2,494)		(2,096)	(7,128)	(6,286)
Amortization of prior service cost	(4)		71	184	212
Amortization of actuarial loss	674		345	2,532	1,035
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	$ 3,080	0	3,080	0
Net periodic pension and postretirement benefit cost	$ 148		$ 187	$ 4,704	$ 563