Securities Available For Sale (Auction Rate Securities Reconciliation Of Cost Basis To Fair Value) (Detail) (USD $)	12 Months Ended			27 Months Ended		39 Months Ended						12 Months Ended					39 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Auction Rate Securities [Member]		Dec. 31, 2012 Auction Rate Securities [Member]		Dec. 31, 2012 Asset-backed Securities [Member] Auction Rate Securities [Member]		Dec. 31, 2011 Asset-backed Securities [Member] Auction Rate Securities [Member]		Dec. 31, 2012 Collateralized Debt Obligations [Member] Auction Rate Securities [Member]		Dec. 31, 2011 Collateralized Debt Obligations [Member] Auction Rate Securities [Member]		Dec. 31, 2010 Collateralized Debt Obligations [Member] Auction Rate Securities [Member]	Dec. 31, 2012 Collateralized Debt Obligations [Member] Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost Basis				$ 14,600,000	[1]	$ 14,600,000	[1]	$ 12,900,000	[1]	$ 12,900,000	[1]	$ 1,700,000	[1]	$ 1,700,000	[1]		$ 1,700,000	[1]
Gross Cumulative Unrealized (Losses)/Gains								(1,200,000)		(1,000,000)
Fair Value								11,700,000		11,900,000
Gross Cumulative Unrealized (Losses)/Gains												1,000,000		0			1,000,000
Gross Cumulative Unrealized (Losses)/Gains				(1,000,000)		(200,000)
Fair Value				13,600,000	[2]	14,400,000	[2]					2,700,000		1,700,000			2,700,000
Cumulative credit and other losses recognized in earnings	0	574,000	1,164,000	3,300,000		3,300,000						0		600,000		1,200,000	3,300,000
Par value of securities held				$ 17,900,000		$ 17,900,000						$ 5,000,000					$ 5,000,000

[1] Adjusted cost basis reflects adjustments for credit and other losses recognized in earnings on our structured finance security. Cumulative adjustments to the cost basis of securities held as of both December 31, 2012 and 2011 totaled $3.3 million. Par value of securities held as of both December 31, 2012 and 2011 totaled $17.9 million.

[2] The Company’s auction rate securities maintain split ratings. For purposes of this table, securities are categorized according to their lowest rating.