Change In Accounting Principle (Schedule Of Condensed Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 01, 2012	Dec. 31, 2011
Change in Accounting Principle [Line Items]
Total assets	$ 2,238,148	$ 2,188,639
Total liabilities	689,455	683,579
Common stock	23,302	22,948
Additional paid-in capital	1,302,660	1,293,130
Accumulated other comprehensive (loss) income	4,933	4,746
Retained earnings	217,798	184,236
Total shareholders' equity	1,548,693	1,505,060
Total liabilities and shareholders' equity	2,238,148	2,188,639
Originally Reported [Member]
Change in Accounting Principle [Line Items]
Total assets		2,188,639
Total liabilities		683,579
Common stock		22,948
Additional paid-in capital		1,293,130
Accumulated other comprehensive (loss) income		(129,875)
Retained earnings		318,857
Total shareholders' equity		1,505,060
Total liabilities and shareholders' equity		2,188,639
Effect Of Accounting Change [Member]
Change in Accounting Principle [Line Items]
Accumulated other comprehensive (loss) income		134,621
Retained earnings		$ (134,621)