Schedule IV - Reinsurance (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross									$ 925,776	$ 793,161	$ 221,933
Ceded to Other Companies									(289,871)	(226,304)	(19,782)
Assumed from Other Companies									203,166	79,593	37,656
Net Amount	$ 197,091	$ 231,051	$ 212,023	$ 198,906	$ 171,889	$ 195,987	$ 216,916	$ 61,658	839,071	646,450	239,807
Life Reinsurance in Force
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross									11,341,727	13,880,064	15,670,436
Ceded to Other Companies									(2,916,911)	(3,348,634)	(3,824,429)
Assumed from Other Companies									4,967,356	5,392,314	5,837,708
Net Amount									$ 13,392,172	$ 15,923,744	$ 17,683,715
Percentage of Amount Assumed to Net									37.10%	33.90%	33.00%
Property and Casualty
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross									$ 854,856	$ 703,281	$ 134,402
Ceded to Other Companies									(283,489)	(217,383)	(11,651)
Assumed from Other Companies									180,823	54,848	22,072
Net Amount									$ 752,190	$ 540,746	$ 144,823
Percentage of Amount Assumed to Net									24.00%	10.10%	15.20%
Life and Annuities
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross									$ 70,920	$ 89,880	$ 87,531
Ceded to Other Companies									(6,382)	(8,921)	(8,131)
Assumed from Other Companies									22,343	24,745	15,584
Net Amount									$ 86,881	$ 105,704	$ 94,984
Percentage of Amount Assumed to Net									25.70%	23.40%	16.40%