Pension and Other Postretirement Benefits (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 42,016	[1]	$ (73,168)	[1]	$ 15,741	[1]
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss	(48,957)
Amortization of prior service costs (credits)	570
Amortization of actuarial loss	6,477
Foreign exchange rate changes	1,765
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(40,145)
Other postretirement benefit plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss	(1,930)
Amortization of prior service costs (credits)	(544)
Amortization of actuarial loss	628
Foreign exchange rate changes	(25)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ (1,871)

[1] Net of tax of $(24,799), $43,109 and $(7,994) for the years ended December 31, 2014, 2013 and 2012, respectively.