Information for Financial Instruments on Which Fair Value Option was Elected (Detail) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Fair Value, Option, Quantitative Disclosures [Line Items]
(Deficiency) of fair value over uncollected principal		$ (93,071)	$ (93,217)
Fair value of financial instruments more than one day past due	[1]		1,088
(Deficiency) of fair value more than one day past due over uncollected principal	[1]	(1,784)	(5,620)
Corporate Bonds
Fair Value, Option, Quantitative Disclosures [Line Items]
(Deficiency) of fair value over uncollected principal		(6,588)	(6,046)
Fair value of financial instruments more than one day past due		0	0
Corporate Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
(Deficiency) of fair value over uncollected principal		(71,562)	(77,900)
Fair value of financial instruments more than one day past due	[1]		1,088
(Deficiency) of fair value more than one day past due over uncollected principal	[1]	(1,784)	(5,620)
Debt Securities
Fair Value, Option, Quantitative Disclosures [Line Items]
(Deficiency) of fair value over uncollected principal		(1,115)	(426)
Loans and Receivables
Fair Value, Option, Quantitative Disclosures [Line Items]
(Deficiency) of fair value over uncollected principal		$ (13,806)	(8,845)
Fair value of financial instruments more than one day past due			$ 0

[1] Corporate Loans and Corporate Bonds within CLO assets are classified as past due if contractual payments are more than one day past due.