Capital Stock (Schedule Of Common Stock Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Class of Stock [Line Items]
Restricted stock expense	$ 4,370	$ 4,063	$ 3,027
Stock option expense	2,343	2,748	2,465
Treasury shares purchased	(266,231)	(265,606)
Balance, shares	36,692,590	36,519,726
Common Stock [Member]
Class of Stock [Line Items]
Balance, shares	62,081,391	62,081,391	62,081,391	62,081,391
Balance	88,629	74,269	69,607
Restricted stock awards	(542)	(850)	(934)
Restricted stock expense	4,376	4,103	3,128
Restricted stock forfeitures	(6)	(40)	(101)
Stock options exercised	825	4,413	122
Stock option expense	2,343	2,748	2,620
Stock option forfeitures			(155)
Performance stock expense	1,019	524	375
Performance stock forfeitures			(7)
Tax provision related to stock plans	632	3,462	(386)
Balance	97,276	88,629	74,269
Stock Compensation Trust [Member]
Class of Stock [Line Items]
Balance, shares	(1,162,784)	(1,360,714)	(2,174,204)	(2,378,462)
Balance	(7,103)	(11,349)	(12,416)
Restricted stock awards	542	850	934
Restricted stock awards, shares	103,815	162,925	178,692
Stock options exercised	491	3,396	133
Stock options exercised, shares	94,115	650,565	25,566
Balance	(6,070)	(7,103)	(11,349)
Treasury [Member]
Class of Stock [Line Items]
Balance, shares	(24,226,017)	(24,200,951)	(23,934,669)	(23,916,639)
Balance	(263,855)	(256,283)	(256,077)
Restricted stock forfeitures, shares	(7,469)	(1,092)	(8,369)
Treasury shares purchased, shares	(17,597)	(265,190)	(9,661)
Treasury shares purchased	(624)	(7,572)	(206)
Balance	$ 264,479	$ (263,855)	$ (256,283)