Income Taxes (Schedule Of Income Tax Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Current provision (benefit), Federal		$ 3,872	$ 3,804	$ (52,792)
Current provision (benefit), State and local		34	4,156	179
Current provision (benefit), Foreign		2,566	2,228	1,589
Current provision (benefit)	(3,300)	6,472	10,188	(51,024)
Deferred provision (benefit), Federal		45,920	85,106	63,509
Federal net operating loss		11,166	(40,057)
Deferred provision (benefit), State and local		5,270	4,544	2,533
Deferred provision (benefit), Foreign		(2,420)	(152)	(2,446)
Deferred provision (benefit)		59,936	49,441	63,596
Income tax provision		$ 66,408	$ 59,629	$ 12,572