Fair Value (Changes In Fair Value Of Assets Measured Using Significant Unobservable Inputs) (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Beginning balance	$ 51,583	$ 66,014	$ 65,559	$ 92,723
Realized in earnings	11	19	(186)	6,230
Unrealized in other comprehensive income	867	(88)	3,239	(2,925)
Purchases	0	167	17,000	3,334
Sales/calls	(146)	0	(33,297)	(15,720)
Settlements	0	(80)	0	(17,610)
Ending balance	52,315	66,032	52,315	66,032
Auction Rate Securities [Member]
Beginning balance	21,054	51,473	51,806	68,814
Realized in earnings	0	0	16	16
Unrealized in other comprehensive income	486	(54)	2,243	1,314
Purchases	0	0	0	0
Sales/calls	(100)	0	(32,625)	(2,500)
Settlements	0	(50)	0	(16,275)
Ending balance	21,440	51,369	21,440	51,369
Private Placements/Venture Capital [Member]
Beginning balance	30,529	14,541	13,753	23,909
Realized in earnings	11	19	(202)	6,214
Unrealized in other comprehensive income	381	(34)	996	(4,239)
Purchases	0	167	17,000	3,334
Sales/calls	(46)	0	(672)	(13,220)
Settlements	0	(30)	0	(1,335)
Ending balance	$ 30,875	$ 14,663	$ 30,875	$ 14,663

This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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- Definition

This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in other comprehensive income (a separate component of shareholders' equity).

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- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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- Definition

Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

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- Definition

Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

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- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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