Employee Benefit Plans - Changes Recognized in OCI (Details) (Defined Benefit Plans, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Current year actuarial gain/(loss)	$ (75,527)	$ 52,063	$ (30,761)
Amortization of actuarial loss	2,861	4,192	4,246
Amortization of prior service cost	0	0	4
Total	$ (72,666)	$ 56,255	$ (26,511)