Income Taxes - Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Apr. 30, 2013
Deferred tax liabilities:
Insurance intangible	$ 493,822,000	$ 559,288,000
Variable interest entities	14,149,000	131,137,000
Investments	138,072,000	168,653,000
Unearned premiums and credit fees	104,589,000	38,826,000
Other	33,835,000us-gaap_DeferredTaxLiabilitiesOther	2,221,000us-gaap_DeferredTaxLiabilitiesOther
Total deferred tax liabilities	784,467,000us-gaap_DeferredTaxLiabilities	900,125,000us-gaap_DeferredTaxLiabilities
Deferred tax assets:
Net operating loss and capital carryforward	1,890,551,000	2,177,029,000
Loss reserves	185,881,000	634,692,000
Compensation	5,276,000	8,724,000
AMT Credits	10,359,000	4,269,000	60,000,000
Other	9,539,000us-gaap_DeferredTaxAssetsOther	58,581,000us-gaap_DeferredTaxAssetsOther
Sub total deferred tax assets	2,101,606,000us-gaap_DeferredTaxAssetsGross	2,883,295,000us-gaap_DeferredTaxAssetsGross
Valuation allowance	1,319,218,000	1,985,369,000
Total deferred tax assets	782,388,000us-gaap_DeferredTaxAssetsNet	897,926,000us-gaap_DeferredTaxAssetsNet
Net deferred tax asset (liability)	$ (2,079,000)us-gaap_DeferredTaxAssetsLiabilitiesNet	$ (2,199,000)us-gaap_DeferredTaxAssetsLiabilitiesNet

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