Fair Value Measurements and Derivative Instruments (Details 2) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Derivative [Line Items]
Other current assets and prepayments: Foreign exchange contracts	$ 603,000				$ 603,000				$ 546,000
Accounts payable and accrued liabilities: Foreign exchange contracts	(303,000)				(303,000)				(526,000)
Other current assets and prepayments: Foreign exchange contracts	329,000				329,000				812,000
Accounts payable and accrued liabilities: Foreign exchange contracts	(3,206,000)				(3,206,000)				(2,483,000)
Total derivative assets	932,000				932,000				1,358,000
Total derivative liabilities	(3,509,000)				(3,509,000)				(3,009,000)
Total net derivative liabilities	(2,577,000)				(2,577,000)				(1,651,000)
Derivative Gain Recognized in Earnings	774,000		2,768,000
Hedged Item Expense Recognized in Earnings	(2,742,000)		(8,227,000)
Total notional amount of outstanding contracts in cash flow hedging relationships	26,000,000				26,000,000				26,000,000
Derivative Gain (Loss) Recognized in AOCI (Effective Portion) - Foreign exchange contracts	17,000		170,000		(52,000)		800,000
Derivative Gain (Loss) Recognized in AOCI (Effective Portion) - Revenue	(958,450,000)		(950,662,000)		(1,895,947,000)		(1,860,025,000)
Derivative Gain (Loss) Recognized in Earnings - Foreign exchange contracts - Selling, general and administrative expenses	(2,622,000)		(1,644,000)		(3,304,000)		(5,995,000)
Amount of collateral that would be required to be posted if our long-term senior unsecured debt ratings was to have fallen below BB-/Ba3	3,000,000				3,000,000
Gain (Loss) Reclassified from AOCI to Earnings (Effective Portion)
Derivative [Line Items]
Derivative Gain (Loss) Recognized in AOCI (Effective Portion) - Revenue	346,000	[1]	371,000	[1]	580,000	[1]	753,000	[1]
Derivative Gain (Loss) Recognized in AOCI (Effective Portion) - Cost of sales	153,000	[1]	286,000	[1]	352,000	[1]	412,000	[1]
Derivative Gain (Loss) Recognized in AOCI (Effective Portion)	$ (193,000)		$ (85,000)		$ (228,000)		$ (341,000)

[1] Amounts in parentheses indicate debits (reductions) to income.