Background and Business Description - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($) Segment $ / shares shares	Dec. 31, 2015 $ / shares shares	Apr. 30, 2013 $ / shares shares
Background And Basis Of Presentation [Line Items]
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Number of reportable segments | Segment	2
Investment Warrants Expiration Date	Apr. 30, 2023
Payment of permitted policy claim (percent)		25.00%
Common stock, shares authorized	130,000,000	130,000,000
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Common stock, shares issued	45,121,788	45,044,222
Warrants Distributed In Bankruptcy			5,047,138
Warrants issued exercise price | $ / shares			$ 16.67
Ambac Assurance [Member]
Background And Basis Of Presentation [Line Items]
Net par exposure for policies allocated to the Segregated Account | $	$ 13,260,537,000
Minimum surplus amount | $	100,000,000
Statutory Accounting Practices, Statutory Capital and Surplus, Balance | $	$ 754,609
Successor [Member]
Background And Basis Of Presentation [Line Items]
Common stock, shares issued			45,000,000
Warrants Distributed In Bankruptcy			5,047,138