Fair Value Measurements (Summary Of Changes In Level 3 Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Fair Value Disclosures [Abstract]
Derivatives, beginning of period	$ 17,130		$ 24,596		$ 29,331		$ 25,228
Total losses (gains) included in net income	(1,480)		3,319		(13,681)		2,687
Total losses (gains) included in other comprehensive income (loss)	0		0		0		0
Transfers into Level 3	0		0		0		0
Transfers out of Level 3	0		0		0		0
Derivatives, end of period	15,650		27,915		15,650		27,915
Net unrealized losses (gains) included in net income relating to liabilities held at September 30, 2012 and 2011	$ (1,480)	[1]	$ 3,319	[1]	$ (13,681)	[1]	$ 2,687	[1]

[1] Included in net investment income in the consolidated statements of income and comprehensive income (loss).