Financial Guarantee Insurance Contracts - Summarized Future Gross Undiscounted Premiums Expected to be Collected, and Future Expected Premiums Earned, Net of Reinsurance (Detail) $ in Thousands	Sep. 30, 2019 USD ($)
Future premiums expected to be collected, December 31, 2019	$ 11,888
Future premiums expected to be collected, December 31, 2020	41,442
Future premiums expected to be collected, December 31, 2021	35,601
Future premiums expected to be collected, December 31, 2022	35,292
Future premiums expected to be collected, December 31, 2023	33,792
Future premiums expected to be collected, December 31, 2028	147,828
Future premiums expected to be collected, December 31, 2033	108,291
Future premiums expected to be collected, December 31, 2038	57,282
Future premiums expected to be collected, December 31, 2043	24,772
Future premiums expected to be collected, December 31, 2048	11,298
Future premiums expected to be collected, December 31, 2053	2,251
Future premiums expected to be collected, December 31, 2058	31
Future premiums expected to be collected, Total	509,768
Future expected premiums to be earned, net of reinsurance, December 31, 2019	10,507
Future expected premiums to be earned, net of reinsurance, December 31, 2020	40,407
Future expected premiums to be earned, net of reinsurance, December 31, 2021	36,938
Future expected premiums to be earned, net of reinsurance, December 31, 2022	34,531
Future expected premiums to be earned, net of reinsurance, December 31, 2023	32,345
Future expected premiums to be earned, net of reinsurance, December 31, 2028	135,566
Future expected premiums to be earned, net of reinsurance, December 31, 2033	90,347
Future expected premiums to be earned, net of reinsurance, December 31, 2038	46,459
Future expected premiums to be earned, net of reinsurance, December 31, 2043	16,205
Future expected premiums to be earned, net of reinsurance, December 31, 2048	6,637
Future expected premiums to be earned, net of reinsurance, December 31, 2053	1,314
Future expected premiums to be earned, net of reinsurance, December 31, 2058	20
Future expected premiums to be earned, net of reinsurance, Total	$ 451,276

Amount of unearned premium revenue under contracts issued by an insurance entity that provide protection to the holder of a financial obligation from a financial loss in the event of a default.

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of premium revenue under financial guarantee insurance contracts expected to be recognized in the fourth fiscal quarter following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6933581&loc=SL5749298-161291

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of premium revenue under financial guarantee insurance contracts expected to be recognized in the eleventh through fifteenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References