Secured Debt Agreements, Net - Additional Information (Detail)		3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($) ExtensionOptions	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($) ExtensionOptions	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) ExtensionOptions	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Maturity date					Feb. 28, 2017
Secured debt agreements borrowings outstanding	$ 5,716,354,000				$ 5,716,354,000	$ 6,116,105,000
Interest expense					184,270,000	152,416,000	$ 69,143,000
Secured debt agreements borrowings outstanding	5,731,626,000				5,731,626,000	6,131,751,000
Covenants, minimum tangible net worth	$ 1,900,000,000				$ 1,900,000,000
Covenants, percentage of tangible assets on cash proceeds from equity issuances					75.00%
Covenants, percentage of recourse indebtedness	5.00%				5.00%
Maximum [Member]
Debt Instrument [Line Items]
Covenants, indebtedness to total assets, in percent	83.33%				83.33%
Minimum [Member]
Debt Instrument [Line Items]
Covenants, EBITDA to fixed charges, in percent					140.00%
Covenants, minimum cash liquidity amount	$ 10,000,000				$ 10,000,000
Asset-Specific Financings [Member]
Debt Instrument [Line Items]
Weighted-average outstanding balance					584,700,000	574,300,000
Revolving Repurchase Facilities [Member]
Debt Instrument [Line Items]
Weighted-average outstanding balance					3,000,000,000	2,200,000,000
Aggregate borrowings	3,600,000,000				$ 3,600,000,000	$ 2,500,000,000
Weighted-average advance rate					79.10%	78.80%
Weighted-average initial maturity					1 year 6 months	1 year 3 months 18 days
Maximum Facility Size	5,479,180,000				$ 5,479,180,000	$ 4,332,267,000
Amount available for potential future fundings of loan	541,743,000				541,743,000	487,028,000
Current borrowing capacity	4,114,580,000				4,114,580,000	2,982,833,000
Secured debt agreements borrowings outstanding	3,572,837,000				$ 3,572,837,000	2,495,805,000
Revolving Repurchase Facilities [Member] | Wells Fargo [Member]
Debt Instrument [Line Items]
Weighted-average advance rate					79.70%
Maximum Facility Size	2,000,000,000				$ 2,000,000,000	1,000,000,000
Amount available for potential future fundings of loan	232,209,000				$ 232,209,000	124,818,000
Borrowings maturity term					Term matched
Current borrowing capacity	1,339,942,000				$ 1,339,942,000	687,200,000
GE Portfolio Acquisition Facility [Member]
Debt Instrument [Line Items]
Secured debt agreements borrowings outstanding	1,479,582,000				1,479,582,000	3,161,291,000
GE Portfolio Acquisition Facility [Member] | Sequential Repay Advance [Member]
Debt Instrument [Line Items]
Term of maturity date			1 year
Secured debt agreements borrowings outstanding						40,700,000
Current borrowing capacity			$ 237,200,000
Percentage of additional advance			5.00%
Sequential Repay Advance, percentage of guarantee rate			100.00%
GE Portfolio Acquisition Facility [Member] | Wells Fargo [Member]
Debt Instrument [Line Items]
Maximum Facility Size	1,700,000,000				1,700,000,000
Approximate credit line, outstanding amount	1,500,000,000
Amount available for potential future fundings of loan	178,200,000				$ 178,200,000
Additional credit capacity		$ 125,000,000
GE Portfolio Acquisition Facility [Member] | Asset Specific Borrowings [Member]
Debt Instrument [Line Items]
Weighted average rate			80.00%
Maturity date					May 20, 2020
Borrowings maturity term					The asset-specific borrowings are term matched to the underlying collateral assets with an outside maturity date of May 20, 2020, which may be extended pursuant to two one-year extension options.
Number of extension options | ExtensionOptions			2
Term of maturity date			1 year
Secured debt agreements borrowings outstanding	1,500,000,000				$ 1,500,000,000	$ 3,100,000,000
GE Portfolio Acquisition Facility [Member] | Asset Specific Borrowings [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of guarantee rate			25.00%
Guarantee of outstanding borrowings			$ 250,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Weighted-average outstanding balance					31,600,000
Interest expense					1,400,000
Amortization of deferred fees and expenses					376,000
Secured debt agreements borrowings outstanding	$ 0				$ 0
Revolving Credit Facility [Member] | Barclays [Member]
Debt Instrument [Line Items]
Maximum Facility Size		$ 125,000,000		$ 125,000,000
Number of extension options | ExtensionOptions	2				2
Term of maturity date					1 year
First mortgage bridge to term financing maximum period				6 months
Base Rate [Member] | GE Portfolio Acquisition Facility [Member] | Asset Specific Borrowings [Member] | Primary [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent			1.75%
Base Rate [Member] | GE Portfolio Acquisition Facility [Member] | Asset Specific Borrowings [Member] | Primary [Member] | Year Four [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent			1.80%
Base Rate [Member] | GE Portfolio Acquisition Facility [Member] | Asset Specific Borrowings [Member] | Primary [Member] | Year Five [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent			1.85%
LIBOR [Member] | Revolving Repurchase Facilities [Member] | Wells Fargo [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent					1.79%
LIBOR [Member] | Revolving Repurchase Facilities [Member] | Weighted-Average Cash Coupon [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent					1.82%	1.83%
LIBOR [Member] | Revolving Repurchase Facilities [Member] | Weighted-Average All-in Cost of Credit [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent					2.02%	2.05%
LIBOR [Member] | GE Portfolio Acquisition Facility [Member] | Sequential Repay Advance [Member]
Debt Instrument [Line Items]
Basis spread on debt obligation, in percent			3.10%
LIBOR basis spread on debt obligation					30-day LIBOR