Segment Information - Summary of Results of Operations Measured as Income from Continuing Operations Before Federal Income Taxes and Equity in Earnings (Losses) of Unconsolidated Affiliates by Operating Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	$ 46,660	$ 94,775	$ 187,426	$ 235,165
Life [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	10,193	10,794	25,523	22,076
Annuity [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	4,433	24,366	38,668	70,415
Accident and Health [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	(11,178)	9,304	1,725	19,579
Property and Casualty [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	33,980	30,088	42,758	59,790
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations	$ 9,232	$ 20,223	$ 78,752	$ 63,305