Segments of Business - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) Segment	Jun. 30, 2014 Segment	Jun. 30, 2015 USD ($) Segment	Jun. 30, 2014 Segment	Dec. 31, 2014 USD ($)	Apr. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2	2	2	2
Identifiable assets	$ 23,928,288		$ 23,928,288		$ 23,489,436
Stockholders' equity (deficit)	7,641,705		7,641,705		$ 7,473,428
Corporate activities
Segment Reporting Information [Line Items]
Identifiable assets	700,000		700,000
Cash and invested assets	400,000		400,000
Stockholders' equity (deficit)	(400,000)		(400,000)
Corporate activities | SORC
Segment Reporting Information [Line Items]
Current borrowing capacity	6,200		6,200
Credit facility borrowings outstanding	6,200		6,200
Secured bank credit facility						$ 250,000
Corporate activities | Kentucky Trailer
Segment Reporting Information [Line Items]
Mortgage loan and borrowings under a credit facility	27,700		27,700
Operating Segments | Reinsurance Segment
Segment Reporting Information [Line Items]
Identifiable assets	16,700,000		16,700,000
Cash and invested assets	14,400,000		14,400,000
Stockholders' equity (deficit)	5,200,000		5,200,000
Operating Segments | Insurance Segment
Segment Reporting Information [Line Items]
Identifiable assets	6,500,000		6,500,000
Cash and invested assets	4,900,000		4,900,000
Stockholders' equity (deficit)	$ 2,800,000		$ 2,800,000