Investment Securities (Summary Of Unrealized Loss Positions Of Available For Sale TRUP CDO's) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Fair Value	$ 59,026	$ 62,795
Unrealized Loss	58,137	68,124
Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	105,489
Fair Value	47,834
Unrealized Loss	57,655
Senior - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	8,485
Fair Value	5,593
Unrealized Loss	2,892
Senior - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	9,142
Fair Value	7,056
Unrealized Loss	2,086
Mezzanine - Bank (now in senior position) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	11,726
Fair Value	5,820
Unrealized Loss	5,906
Mezzanine - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	53,728
Fair Value	17,583
Unrealized Loss	36,145
Mezzanine - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	6,500
Fair Value	3,355
Unrealized Loss	3,145
Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	5,218
Fair Value	1,206
Unrealized Loss	4,012
Single Issue Trust Preferreds [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	10,690
Fair Value	7,221
Unrealized Loss	3,469
Investment Grade [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	9,142
Investment Grade [Member] | Senior - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Investment Grade [Member] | Senior - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	9,142
Investment Grade [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Investment Grade [Member] | Mezzanine - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Investment Grade [Member] | Mezzanine - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Investment Grade [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Investment Grade [Member] | Single Issue Trust Preferreds [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	5,000
Split Rated [Member] | Senior - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	5,000
Split Rated [Member] | Senior - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Mezzanine - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Mezzanine - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Split Rated [Member] | Single Issue Trust Preferreds [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Below Investment Grade [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	91,347
Below Investment Grade [Member] | Senior - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	3,485
Below Investment Grade [Member] | Senior - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	0
Below Investment Grade [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	11,726
Below Investment Grade [Member] | Mezzanine - Bank [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	53,728
Below Investment Grade [Member] | Mezzanine - Insurance [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	6,500
Below Investment Grade [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	5,218
Below Investment Grade [Member] | Single Issue Trust Preferreds [Member]
Schedule of Investments [Line Items]
Amortized Cost	10,690
Below Investment Grade [Member] | Single Issue Trust Preferreds [Member] | Trup CDOs And Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	$ 10,690