Pooled Trust Preferred Securities that Have at Least One Credit Rating Below Investment Grade (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 Entity
INCAPS Funding I Class B-2 Notes
Schedule of Investments [Line Items]
Lowest credit rating assigned to security	CCC
Number of banks/insurance companies currently performing	19
Actual deferrals and defaults as a percentage of original collateral	9.00%
Expected deferrals and defaults as a percentage of remaining performing collateral	22.00%
Expected recoveries as a percentage of remaining performing collateral
Excess subordination as a percentage of remaining performing collateral	22.00%
INCAPS Funding I Class B-2 Notes | Trust Preferred Securities
Schedule of Investments [Line Items]
Book value	$ 14,964
Fair value	19,319
Unrealized gain (loss)	4,355
Alesco Preferred Funding VII Ltd. Class C-1 Notes
Schedule of Investments [Line Items]
Lowest credit rating assigned to security	C
Number of banks/insurance companies currently performing	52
Actual deferrals and defaults as a percentage of original collateral	17.00%
Expected deferrals and defaults as a percentage of remaining performing collateral	25.00%
Expected recoveries as a percentage of remaining performing collateral
Alesco Preferred Funding VII Ltd. Class C-1 Notes | Trust Preferred Securities
Schedule of Investments [Line Items]
Book value	553
Fair value	574
Unrealized gain (loss)	21
Preferred Term Securities II Mezzanine Notes
Schedule of Investments [Line Items]
Lowest credit rating assigned to security	C
Number of banks/insurance companies currently performing	10
Actual deferrals and defaults as a percentage of original collateral	26.00%
Expected deferrals and defaults as a percentage of remaining performing collateral	46.00%
Expected recoveries as a percentage of remaining performing collateral
Preferred Term Securities II Mezzanine Notes | Trust Preferred Securities
Schedule of Investments [Line Items]
Book value	452
Fair value	952
Unrealized gain (loss)	$ 500