Other Assets, Other Long-term Liabilities and Other Income (Expense), Net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Assets
Insurance claim receivable	$ 34,839	$ 39,309
Deferred income taxes	22,877	29,840
Deferred costs	7,711	11,150
Mineral reserves	3,199	3,199
Deposits	677	997
Other long-term assets	6,311	1,223
Other assets	75,614	85,718
Other Long-term Liabilities
Acquisition related liabilities	51,102	50,624
Insurance claim payable	34,774	39,309
Pension liability	19,831	35,472
Employee benefit related liabilities	2,536	3,524
Mineral royalties payable	1,727	1,859
Deferred lease incentive	1,143	1,241
Subcontractor insurance program		962
Other	6,745	6,005
Other Long-term Liabilities	117,858	138,996
Other Income (Expense), Net
Interest income	8,745	2,842	2,764
Gain on sale of property used in operations		456	726
Adjustment of investments to fair value			(4,750)
Adjustment of acquisition related liabilities	(26,374)	(256)	7,296
Amortization of deferred costs	(1,844)	(1,585)	(1,399)
Bank Fees	(1,559)	(2,090)	(1,549)
Realized loss on sale of investments, net	72	(2,699)	(10)
Miscellaneous Income (expense), net	2,385	1,475	1,343
Total other Income (Expense), net	$ (18,575)	$ (1,857)	$ 4,421