Financial Guarantee Insurance Contracts - Estimated Future Amortization Expense for Insurance Intangible Asset (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Insurance Intangible Asset [Member]
Amortization Of Intangible Assets [Line Items]
2015	$ 94,815								$ 94,815
2016	81,469								81,469
2017	72,967								72,967
2018	67,115								67,115
2019	60,621								60,621
Thereafter	585,093								585,093
Successor [Member]
Amortization Of Intangible Assets [Line Items]
Amortization of insurance intangible assets	40,152	$ 44,553	$ 39,013	$ 50,890	$ 54,357	$ 39,680	$ 38,088	$ 37,432	174,608	$ 169,557	$ 151,830
Intangible Assets, Gross (Excluding Goodwill)	1,534,419				1,626,566				1,534,419	1,626,566
Accumulated amortization on insurance intangible asset	$ 572,339				$ 414,454				572,339	414,454
Successor [Member] | Insurance Asset [Member]
Amortization Of Intangible Assets [Line Items]
Amortization of insurance intangible assets									$ 174,608	$ 169,557	$ 151,830