Derivatives (Narrative) (Details)	3 Months Ended	6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Dec. 31, 2010 USD ($)	Jun. 30, 2011 Multi-Service Vessel [Member] USD ($)	Jun. 30, 2011 Multi-Service Vessel [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2010 Multi-Service Vessel [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2011 Multi-Service Vessel [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2010 Multi-Service Vessel [Member] Forward Contracts [Member] USD ($)	Dec. 31, 2010 Multi-Service Vessel [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2011 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2010 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2011 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] USD ($)	Jun. 30, 2010 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] USD ($)	Mar. 31, 2011 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] SGD	Dec. 31, 2010 Asia Pacific Operating Expenses [Member] Forward Contracts [Member] USD ($)
Ineffective portion of the hedging relationship	$ 0	$ 0
Unrealized gains, net of taxes, in Accumulated other comprehensive income (loss)	(8,822,000)	(8,822,000)	(8,770,000)	100,000
Expected to be realized in earnings				100,000
Prepaid expenses and other	27,950,000	27,950,000	34,099,000		200,000		200,000		300,000	100,000		100,000			500,000
Gains included in cost of operations					500,000	100,000	700,000	200,000
Notional amount of foreign currency derivatives														5,000,000
Gain (loss) recorded in other income (expense)										$ (500,000)	$ 100,000	$ (400,000)	$ (700,000)