Fair Value Measurements - Summary of Information about Described Model Inputs Used to Determine Fair Value of Each Class of Credit Derivatives (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Notional outstanding	$ 2,491,138	$ 2,776,103
Successor Ambac [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Notional outstanding	2,491,138	2,776,103
Successor Ambac [Member] | CLO [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Notional outstanding	1,101,199	1,337,737
Weighted average reference obligation price	$ 98.3	$ 98.0
Weighted average life (WAL) in years	2 years	2 years 1 month 6 days
Weighted average credit rating	AA	AA
Weighted average relative change ratio	35.30%	35.30%
CVA percentage	11.51%	13.67%
Fair value of derivative liabilities	(5,847)	(7,993)
Successor Ambac [Member] | Other [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Notional outstanding	1,331,019	1,291,371
Weighted average reference obligation price	$ 87.5	$ 85.7
Weighted average life (WAL) in years	5 years 2 months 12 days	5 years 4 months 24 days
Weighted average credit rating	BBB	BBB-
Weighted average relative change ratio	42.80%	43.10%
CVA percentage	26.08%	30.70%
Fair value of derivative liabilities	$ (80,182)	$ (84,780)