Employee Benefit Plans - Components of Expense (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic benefit cost	$ 20,623	$ 19,625	$ 17,949
Defined benefit plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	79	104	48
Interest cost	23,732	25,830	25,931
Expected return on plan assets, net of expenses	(21,501)	(22,520)	(23,009)
Amortization of actuarial (gain)/loss	4,192	3,586	2,984
Curtailments/Settlement losses	0	664	8
Total for defined benefit plans	6,502	7,664	5,962
Multi-employer plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic benefit cost	407	467	467
SERP
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0	0
Interest cost	749	721
Net periodic benefit cost	2,335	956	2,044
Defined contribution plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic benefit cost	$ 11,379	$ 10,538	$ 9,476