Financial Guarantee Insurance Contracts - Estimated Future Amortization Expense for Insurance Intangible Asset (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Amortization Of Intangible Assets [Line Items]
Amortization of insurance intangible assets	$ 45,690	$ 44,553	$ 116,686	$ 134,456
Intangible Assets, Gross (Excluding Goodwill)	1,576,788		1,576,788		$ 1,534,419
Accumulated amortization on insurance intangible asset	698,816		698,816		572,339
2016	22,983		22,983
2017	78,847		78,847
2018	70,336		70,336
2019	65,037		65,037
2020	59,216		59,216
Thereafter	581,553		581,553
Insurance intangible asset	$ 877,972		$ 877,972		$ 962,080