Financial Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Financial Instruments (Textuals) [Abstract]
Line Of Credit Facility Forecasted Borrowing Amount	$ 100,000,000
Derivative, Fixed Interest Rate	3.24%
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	7,477,000	8,172,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	(61,000)	(418,000)
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedge, Net of Tax, Accumulated Other Comprehensive Income (Loss)		(300,000)
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(755,000)	(736,000)
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net, Net of Tax	(500,000)	(500,000)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(3,054,000)
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	72,793,000		77,980,000
Foreign Currency Cash Flow Hedge Asset at Fair Value	100,000
Foreign Currency Cash Flow Hedge Liability at Fair Value	800,000		400,000
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax	(787,000)
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, After Tax	(600,000)
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(475,000)
Foreign Currency Cash Flow Hedge Gain Loss Reclassified To Earnings, Net, After Tax	(400,000)
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	(734,000)
Foreign Currency Derivative Instruments Not Designated As Hedging Instruments Asset At Fair Value	300,000		400,000
Foreign Currency Derivative Instruments Not Designated As Hedging Instruments Liability At Fair Value	600,000		300,000
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(2,200,000)	1,900,000
Notional Value of Other Derivatives	$ 155,400,000		$ 132,300,000