Comprehensive Earnings (Components Of Other Comprehensive Earnings) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Equity [Abstract]
Unrecognized gain (loss) and prior service cost arising during the period	$ 0	$ 0	$ 0	$ 0
Less: Amortization of prior service cost (gain) included in net earnings	9	(513)	19	(522)
Net change in unrecognized (loss) gain and prior service cost related to post-retirement plans	(9)	513	(19)	522
Amount of (loss) gain recognized in AOCE on derivatives (effective portion)	(48,492)	34	(31,474)	3,647
Less: Reclassification of (loss) gain from AOCE into earnings (effective portion)	(13,686)	1,215	(19,314)	178
Net unrecognized loss on derivatives	(34,806)	(1,181)	(12,160)	3,469
Unrealized gain (loss) on marketable securities	92	241	(51)	(127)
Less: Reclassification for gain included in net earnings	4	4	29	4
Net unrealized gain (loss) on marketable securities	$ 88	$ 237	$ (80)	$ (131)