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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment charge			$ 0	$ (3,080)
Contributions paid	$ 0	$ 0	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	112	250	336	724
Interest cost	1,312	1,722	3,936	5,312
Expected return on assets	(2,035)	(2,494)	(6,105)	(7,128)
Amortization of prior service cost	50	(4)	150	184
Amortization of actuarial loss	406	674	1,218	2,532
Curtailment charge	0	0	0	(3,080)
Net periodic pension and postretirement benefit (credit) cost	$ (155)	$ 148	$ (465)	$ 4,704