Restructuring and Related Charges (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013 item	Sep. 30, 2013
Restructuring and Related Charges
Number of shore-side positions eliminated	500
Restructuring and Related Charges
Balance at the beginning of the period	$ 796,000
Accruals	12,244,000	13,922,000
Payments	1,062,000
Balance at the end of the period	11,978,000	11,978,000
Cumulative Charges Incurred	13,922,000
Expected Additional Expenses to be Incurred	8,615,000
Minimum number of initiatives, which may incur additional charges	1
Additional incremental costs	8,000,000
Termination benefits
Restructuring and Related Charges
Accruals	10,004,000
Payments	387,000
Balance at the end of the period	9,617,000	9,617,000
Cumulative Charges Incurred	10,004,000
Expected Additional Expenses to be Incurred	1,687,000
Contract termination costs
Restructuring and Related Charges
Accruals	200,000
Balance at the end of the period	200,000	200,000
Cumulative Charges Incurred	200,000
Expected Additional Expenses to be Incurred	3,761,000
Other related costs
Restructuring and Related Charges
Balance at the beginning of the period	796,000
Accruals	2,040,000
Payments	675,000
Balance at the end of the period	2,161,000	2,161,000
Cumulative Charges Incurred	3,718,000
Expected Additional Expenses to be Incurred	$ 3,167,000