Fair Value Measurements - Summary of Changes in Level 3 Fair Value Category (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Investment by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 711,490	$ 262,732	$ 488,884	$ 198,201
Included in earnings	14,616	6,908	27,019	12,637
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(4,783)	(38,617)	23,236	(44,323)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	17	150,348	91,892	234,852
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(4,913)	(1,039)	(9,159)	(21,035)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	6,243	0	100,798	0
Balance, end of period	722,670	380,332	722,670	380,332
Derivatives by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(109,894)	(230,201)	(99,192)	(215,346)
Included in earnings	(3,047)	14,489	(11,030)	568
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	8,909	8,185	6,190	7,251
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	88,218	0	88,218
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	(104,032)	(119,309)	(104,032)	(119,309)
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	3,280	(14,081)	11,515	1,933
Credit Derivative [Member] | Derivatives by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(21,929)	(76,377)	(34,543)	(73,459)
Included in earnings	3,955	10,294	16,821	7,795
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(233)	(407)	(485)	(826)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	(18,207)	(66,490)	(18,207)	(66,490)
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	(3,722)	(9,886)	(16,336)	(5,294)
Interest Rate Swaps [Member] | Derivatives by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(87,965)	(153,824)	(64,649)	(141,887)
Included in earnings	(7,002)	4,195	(27,851)	(7,227)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	9,142	8,592	6,675	8,077
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	88,218	0	88,218
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	(85,825)	(52,819)	(85,825)	(52,819)
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	7,002	(4,195)	27,851	7,227
Residential Mortgage-Backed Securities [Member] | Investment by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	639,704	262,732	488,884	194,393
Included in earnings	14,344	6,908	26,458	12,656
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(4,803)	(38,617)	22,171	(44,037)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	17	150,348	91,892	234,852
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(4,655)	(1,039)	(8,646)	(17,532)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	6,243		30,091
Balance, end of period	650,850	380,332	650,850	380,332
Asset-backed Securities [Member] | Investment by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	71,786	0	0	0
Included in earnings	272	0	561	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	20	0	1,065	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(258)	0	(513)	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three			70,707
Balance, end of period	71,820	0	71,820	0
Corporate Debt Securities [Member] | Investment by Class [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	0	0	3,808
Included in earnings		0	0	(19)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss		0	0	(286)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(3,503)
Balance, end of period	0	0	0	0
Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	11,960,555	13,504,326	11,497,098	13,845,454
Included in earnings	366,656	(573,055)	622,647	(218,493)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(883,995)	731,700	(1,110,618)	100,485
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	17	150,348	91,892	234,852
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(48,656)	45,239	(81,666)	194,218
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	6,243	88,218	100,798	88,218
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	(523,249)	0	(737,898)	0
Balance, end of period	12,021,381	13,856,298	12,021,381	13,856,298
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	(351,807)	580,371	(595,133)	233,631
Level 3 [Member] | Investments Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, end of period		2,747,181		2,747,181
Level 3 [Member] | Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, end of period		13,005,216		13,005,216
Level 3 [Member] | Long-Term Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, end of period	(2,258,009)	(2,166,826)	(2,258,009)	(2,166,826)
Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(109,894)	(230,201)	(99,192)	(215,346)
Included in earnings	(3,047)	14,489	(11,030)	568
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(8,909)	(8,185)	(6,190)	(7,251)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	88,218	0	88,218
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	(104,032)	(119,309)	(104,032)	(119,309)
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date		(14,081)	3,280	1,933
Level 3 [Member] | Loans Receivable [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, end of period	11,074,772		11,074,772
Level 3 [Member] | Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	711,490	262,732	488,884	198,201
Included in earnings	14,616	6,908	27,019	12,637
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(4,783)	(38,617)	23,236	(44,323)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	17	150,348	91,892	234,852
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	4,913	1,039	9,159	21,035
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	6,243	0	100,798	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	722,670	380,332	722,670	380,332
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date		0	0	0
Level 3 [Member] | Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	8,411	10,036	8,696	12,036
Included in earnings	276	(332)	(9)	(627)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	0	0	1,705
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	8,687	9,704	8,687	9,704
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	(276)	332	9	627
Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, end of period		(119,309)		(119,309)
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date			(606,667)	231,071
Variable Interest Entity, Primary Beneficiary [Member] | Level 3 [Member] | Long-Term Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(2,788,416)	(2,032,099)	(3,180,170)	(1,263,664)
Included in earnings	(332,605)	(23,091)	(334,557)	(863,089)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	233,100	(111,636)	305,960	(44,011)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(106,663)	0	(212,860)	(3,938)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	(523,249)	0	(737,898)	0
Balance, end of period	(2,258,009)	(2,166,826)	(2,258,009)	(2,166,826)
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date		23,091	332,605	863,089
Variable Interest Entity, Primary Beneficiary [Member] | Level 3 [Member] | Loans Receivable [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	11,516,241	12,789,201	11,690,324	12,371,177
Included in earnings	516,091	(453,769)	676,632	657,158
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(895,557)	722,169	(1,163,959)	159,548
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	62,003	52,385	128,225	182,667
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	11,074,772	13,005,216	11,074,772	13,005,216
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date		453,769	(516,091)	(657,158)
Variable Interest Entity, Primary Beneficiary [Member] | Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	2,622,723	2,704,657	2,588,556	2,743,050
Included in earnings	171,325	(117,260)	264,592	(25,140)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	(216,755)	159,784	(275,855)	29,271
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three	0	0	0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three	0	0	0	0
Balance, end of period	2,577,293	2,747,181	2,577,293	2,747,181
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$ (171,325)	$ 117,260	$ (264,592)	$ 25,140