Reinsurance Balances Recoverable - Summary of Reinsurance Reserves Recoverable (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Effects of Reinsurance [Line Items]
Outstanding losses	$ 755,863	$ 798,798
IBNR	588,474	605,830
Fair value adjustments	(19,607)	(21,154)
Total reinsurance reserves recoverable	1,324,730	1,383,474
Paid losses recoverable	77,486	90,530
Net	1,402,216	1,474,004
Non-Life Run-Off
Effects of Reinsurance [Line Items]
Outstanding losses	550,849	587,164
IBNR	443,499	465,211
Fair value adjustments	(17,252)	(17,628)
Total reinsurance reserves recoverable	977,096	1,034,747
Paid losses recoverable	59,943	72,213
Net	1,037,039	1,106,960
Atrium
Effects of Reinsurance [Line Items]
Outstanding losses	7,337	6,772
IBNR	16,899	16,581
Fair value adjustments	2,013	2,499
Total reinsurance reserves recoverable	26,249	25,852
Paid losses recoverable	653	430
Net	26,902	26,282
StarStone
Effects of Reinsurance [Line Items]
Outstanding losses	175,986	182,076
IBNR	127,775	123,732
Fair value adjustments	(4,368)	(6,025)
Total reinsurance reserves recoverable	299,393	299,783
Paid losses recoverable	16,246	16,568
Net	315,639	316,351
Life and Annuities
Effects of Reinsurance [Line Items]
Outstanding losses	21,691	22,786
IBNR	301	306
Fair value adjustments	0	0
Total reinsurance reserves recoverable	21,992	23,092
Paid losses recoverable	644	1,319
Net	$ 22,636	$ 24,411

Reinsurance receivables fair value adjustments.

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Estimated amount after valuation allowance of reinsurance recoverables, due from reinsurers for incurred claims not yet reported, and claims settlement expenses.

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Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

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Amount, after valuation allowance, recoverable under reinsurance contracts including premium paid under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

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Amount before valuation allowance recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

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Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to and paid by the ceding insurer.

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