Investments in Equity Securities Available for Sale (Investments in Equity Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Cost	$ 457,662	$ 342,393
Gross Unrealized, Gains	115,495	118,799
Gross Unrealized, Losses	(11,372)	(17,753)
Fair Value	561,785	443,439
Carrying Value	561,785	443,439
Common Stock [Member]
Cost	337,557	209,210
Gross Unrealized, Gains	104,104	113,660
Gross Unrealized, Losses	(2,415)	(2,888)
Fair Value	439,246	319,982
Carrying Value	439,246	319,982
Preferred Stock [Member]
Cost	120,105	133,183
Gross Unrealized, Gains	11,391	5,139
Gross Unrealized, Losses	(8,957)	(14,865)
Fair Value	122,539	123,457
Carrying Value	$ 122,539	$ 123,457

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading.

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

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