Business Segments - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Disclosure [Line Items]
Litigation settlement amount not related to insurance operations		$ 2,337
Administrative settlement expense		8,179
Administrative settlement, after tax	$ 0	5,316
Settled Litigation Regarding Investments [Member]
Segment Reporting Disclosure [Line Items]
Litigation settlement expense, after tax		853
Litigation settlement amount related to investments		1,300
Settled Litigation Regarding Non-Insurance Matter [Member]
Segment Reporting Disclosure [Line Items]
Litigation settlement amount not related to insurance operations		3,700
Prior Year Litigation Matter [Member]
Segment Reporting Disclosure [Line Items]
Litigation settlement expense, after tax		$ 2,400