Derivative Financial Instruments (Schedule Of Pretax Effect On Net Income (Loss) And Other Comprehensive Income (Loss) Of Derivative Instruments Classified As Cash Flow Hedges) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Foreign Currency Forwards And Options [Member] | Cost Of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) reclassified from accumulated other comprehensive income (loss) to net income (effective portion)	$ 16	$ 16	$ 33	$ 31
Foreign Currency Forwards And Options [Member] | Selling, General and Administrative Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) reclassified from accumulated other comprehensive income (loss) to net income (effective portion)	(147)	(1,798)	(149)	(2,592)
Cash Flow Derivative Hedges | Aluminum Futures Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) recognized in other comprehensive income (loss)	2,195	(1,201)	3,710	(2,795)
Cash Flow Derivative Hedges | Aluminum Futures Contracts | Cost Of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) reclassified from accumulated other comprehensive income (loss) to net income (effective portion)	1,372	(1,551)	2,012	(2,191)
Cash Flow Derivative Hedges | Foreign Currency Forwards And Options
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) recognized in other comprehensive income (loss)	0	0		0
Cash Flow Derivative Hedges | Foreign Currency Forwards And Options | Cost Of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) recognized in other comprehensive income (loss)			0
Cash Flow Derivative Hedges | Foreign Currency Forwards And Options | Selling, General and Administrative Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain (loss) recognized in other comprehensive income (loss)	$ 1,061	$ (535)	$ (222)	$ (5,360)