Restated Consolidated Statements of Operations (Detail) (USD $)	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Revenues:
Rental income	$ 365,712,000		$ 89,729,000	[1]	$ 924,646,000		$ 183,251,000	[1]
Direct financing lease income	625,000		1,201,000	[1]	2,812,000		1,201,000	[1]
Operating expense reimbursements	30,984,000		4,325,000	[1]	81,716,000		8,516,000	[1]
Total revenues	457,118,000		95,255,000	[1],[2]	1,160,450,000		192,968,000	[1],[2]
Operating expenses:
Acquisition related	13,998,000	[3]	26,948,000	[1],[3]	34,616,000	[3]	74,541,000	[1],[3]
Merger and other non-routine transactions	7,632,000	[4]	4,301,000	[1],[4]	175,352,000	[4]	133,734,000	[1],[4]
Property operating	40,977,000		5,430,000	[1]	110,018,000		11,065,000	[1]
Management fees to affiliate	0		0	[1]	13,888,000		12,493,000	[1]
General and administrative	32,207,000	[5]	9,866,000	[1],[5]	128,711,000	[5]	23,921,000	[1],[5]
Equity-based compensation			0		32,805,000		13,981,000	[1]
Depreciation and amortization	265,150,000		62,136,000	[1]	689,731,000		122,484,000	[1]
Operating fees to affiliate			0				0
Impairment of real estate	2,299,000		2,074,000	[1]	3,855,000		2,074,000	[1]	3,300,000
Total operating expenses	377,661,000		110,755,000	[1],[2]	1,213,073,000		380,312,000	[1],[2]
Operating income	79,457,000		(15,500,000)	[1]	(52,623,000)		(187,344,000)	[1]
Other (expense) income:
Interest expense	(101,643,000)		(27,189,000)	[1]	(326,491,000)		(45,414,000)	[1]
Loss on contingent value rights			0				0
Income from investment securities			0		247,000		0	[1]
Gain (loss) on sale of investment securities	6,357,000		(2,246,000)	[1]	6,357,000		(1,795,000)	[1]
Loss on derivative instruments	(17,484,000)		(38,651,000)	[1]	(10,398,000)		(69,830,000)	[1]
Other income, net	7,556,000		136,000	[1]	29,702,000		2,658,000	[1]
Total other expenses, net	(367,504,000)		(67,950,000)	[1]	(597,862,000)		(114,381,000)	[1]
Loss from continuing operations	(288,047,000)		(83,450,000)	[1]	(650,485,000)		(301,725,000)	[1]
Net (gain) loss from continuing operations attributable to non-controlling interests			3,153,000				7,882,000
Net loss from continuing operations attributable to stockholders			(80,293,000)				(293,843,000)
Discontinued operations:
Net income (loss) from operations of held for sale properties	0		96,000	[1]	0		159,000	[1]
(Loss) gain on held for sale properties			0				0
Net income (loss) from discontinued operations	0		96,000	[1],[2]	0		159,000	[1],[2]
Net (loss) income from discontinued operations attributable to non-controlling interests			0				0
Net income (loss) from discontinued operations attributable to stockholders			96,000				159,000
Net loss	(288,047,000)		(83,354,000)	[1],[2]	(650,485,000)		(301,566,000)	[1],[2]
Net (income) loss attributable to non-controlling interests	7,649,000		3,153,000	[1]	23,923,000		7,882,000	[1]
Net loss attributable to stockholders	(280,398,000)		(80,201,000)	[1]	(626,562,000)		(293,684,000)	[1]
Basic and diluted net loss per share from continuing operations attributable to common stockholders	$ (0.35)		$ (0.36)	[1]	$ (0.94)		$ (1.50)	[1]
Basic and diluted net loss per share attributable to common stockholders			$ (0.36)				$ (1.50)
Adjustments [Member]
Operating expenses:
Equity-based compensation							0
As Previously Reported [Member]
Revenues:
Rental income			56,681,000	[6]			138,060,000	[6]
Direct financing lease income			977,000	[6]			977,000	[6]
Operating expense reimbursements			3,226,000	[6]			6,878,000	[6]
Total revenues			60,884,000	[6]			145,915,000	[6]
Operating expenses:
Acquisition related			1,235,000	[6]			21,961,000	[6]
Merger and other non-routine transactions			3,791,000	[6]			146,240,000	[6]
Property operating			4,103,000	[6]			8,972,000	[6]
Management fees to affiliate			0	[6]			0	[6]
General and administrative			1,586,000	[6]			4,018,000	[6]
Equity-based compensation			7,180,000	[6]			13,895,000	[7]
Depreciation and amortization			39,382,000	[6]			92,211,000	[6]
Operating fees to affiliate			0	[6]			0	[6]
Impairment of real estate			0	[6]			0	[6],[7]
Total operating expenses			57,277,000	[6]			284,912,000	[6]
Operating income			3,607,000	[6]			(138,997,000)	[6]
Other (expense) income:
Interest expense			(24,135,000)	[6]			(41,589,000)	[6]
Loss on contingent value rights			(38,542,000)	[6]			(69,676,000)	[6]
Income from investment securities			0	[6]			218,000	[6]
Gain (loss) on sale of investment securities			0	[6]			451,000	[6],[7]
Loss on derivative instruments			(99,000)	[6]			(144,000)	[6]
Other income, net			45,000	[6]			171,000	[6]
Total other expenses, net			(62,731,000)	[6]			(110,569,000)	[6]
Loss from continuing operations			(59,124,000)	[6]			(249,566,000)	[6]
Net (gain) loss from continuing operations attributable to non-controlling interests			(30,000)	[6]			726,000	[6]
Net loss from continuing operations attributable to stockholders			(59,154,000)	[6]			(248,840,000)	[6]
Discontinued operations:
Net income (loss) from operations of held for sale properties			96,000	[6]			159,000	[6]
(Loss) gain on held for sale properties			0	[6]			14,000	[6]
Net income (loss) from discontinued operations			96,000	[6]			173,000	[6]
Net (loss) income from discontinued operations attributable to non-controlling interests			(5,000)	[6]			(9,000)	[6]
Net income (loss) from discontinued operations attributable to stockholders			91,000	[6]			164,000	[6]
Net loss			(59,028,000)	[6]			(249,393,000)	[6],[7]
Net (income) loss attributable to non-controlling interests			(35,000)	[6]			717,000	[6]
Net loss attributable to stockholders			(59,063,000)	[6]			(248,676,000)	[6]
Basic and diluted net loss per share from continuing operations attributable to common stockholders			$ (0.32)	[6]			$ (1.49)	[6]
Basic and diluted net loss per share attributable to common stockholders			$ (0.32)	[6]			$ (1.49)	[6]
As Previously Reported [Member] | Adjustments [Member]
Operating expenses:
Equity-based compensation							11,510,000	[6]
Reclassifications And Immaterial Adjustments [Member]
Revenues:
Rental income			(6,000)				89,000
Direct financing lease income			0				0
Operating expense reimbursements			6,000				(89,000)
Total revenues			0				0
Operating expenses:
Acquisition related			0				0
Merger and other non-routine transactions			0				0
Property operating			0				0
Management fees to affiliate			0				0
General and administrative			0				34,000
Equity-based compensation			0
Depreciation and amortization			0				(34,000)
Operating fees to affiliate			0				0
Impairment of real estate			0				0
Total operating expenses			0				0
Operating income			0				0
Other (expense) income:
Interest expense			0				0
Loss on contingent value rights			38,542,000				69,676,000
Income from investment securities			0				(2,016,000)
Gain (loss) on sale of investment securities			0				0
Loss on derivative instruments			(38,542,000)				(69,676,000)
Other income, net			0				2,016,000
Total other expenses, net			0				0
Loss from continuing operations			0				0
Net (gain) loss from continuing operations attributable to non-controlling interests			0				0
Net loss from continuing operations attributable to stockholders			0				0
Discontinued operations:
Net income (loss) from operations of held for sale properties			0				0
(Loss) gain on held for sale properties			0				0
Net income (loss) from discontinued operations							0
Net (loss) income from discontinued operations attributable to non-controlling interests			0				0
Net income (loss) from discontinued operations attributable to stockholders			0				0
Net loss			0				0
Net (income) loss attributable to non-controlling interests			0				0
Net loss attributable to stockholders			0				0
Basic and diluted net loss per share from continuing operations attributable to common stockholders			$ 0.00				$ 0.00
Basic and diluted net loss per share attributable to common stockholders			$ 0.00				$ 0.00
Reclassifications And Immaterial Adjustments [Member] | Adjustments [Member]
Operating expenses:
Equity-based compensation							0
Reclassifications And Immaterial Adjustments [Member] | ARCT IV [Member]
Revenues:
Rental income			33,054,000	[8]			45,102,000	[8]
Direct financing lease income			224,000	[8]			224,000	[8]
Operating expense reimbursements			1,093,000	[8]			1,727,000	[8]
Total revenues			34,371,000	[8]			47,053,000	[8]
Operating expenses:
Acquisition related			25,713,000	[8]			52,603,000	[8]
Merger and other non-routine transactions			2,122,000	[8]			3,835,000	[8]
Property operating			1,341,000	[8]			2,107,000	[8]
Management fees to affiliate			0	[8]			0	[8]
General and administrative			822,000	[8]			2,214,000	[8]
Equity-based compensation			0	[8]			18,000	[8]
Depreciation and amortization			23,030,000	[8]			30,620,000	[8]
Operating fees to affiliate			0	[8]			0	[8]
Impairment of real estate			0	[8]			0	[8]
Total operating expenses			53,028,000	[8]			91,379,000	[8]
Operating income			(18,657,000)	[8]			(44,326,000)	[8]
Other (expense) income:
Interest expense			(3,054,000)	[8]			(3,240,000)	[8]
Loss on contingent value rights			0	[8]			0	[8]
Income from investment securities			0	[8]			1,798,000	[8]
Gain (loss) on sale of investment securities			(2,246,000)	[8]			(2,246,000)	[8]
Loss on derivative instruments			0	[8]			0	[8]
Other income, net			44,000	[8]			463,000	[8]
Total other expenses, net			(5,256,000)	[8]			(3,225,000)	[8]
Loss from continuing operations			(23,913,000)	[8]			(47,551,000)	[8]
Net (gain) loss from continuing operations attributable to non-controlling interests			260,000	[8]			415,000	[8]
Net loss from continuing operations attributable to stockholders			(23,653,000)	[8]			(47,136,000)	[8]
Discontinued operations:
Net income (loss) from operations of held for sale properties			0	[8]			0	[8]
(Loss) gain on held for sale properties			0	[8]			0	[8]
Net income (loss) from discontinued operations			0	[8]			0	[8]
Net (loss) income from discontinued operations attributable to non-controlling interests			0	[8]			0	[8]
Net income (loss) from discontinued operations attributable to stockholders			0	[8]			0	[8]
Net loss			(23,913,000)	[8]			(47,551,000)	[8]
Net (income) loss attributable to non-controlling interests			260,000	[8]			415,000	[8]
Net loss attributable to stockholders			(23,653,000)	[8]			(47,136,000)	[8]
Basic and diluted net loss per share from continuing operations attributable to common stockholders			$ 0.00	[8]			$ 0.00	[8]
Basic and diluted net loss per share attributable to common stockholders			$ 0.00	[8]			$ 0.00	[8]
Reclassifications And Immaterial Adjustments [Member] | ARCT IV [Member] | Adjustments [Member]
Operating expenses:
Equity-based compensation							0	[8]
Error Corrections [Member]
Revenues:
Rental income			0				0
Direct financing lease income			0				0
Operating expense reimbursements			0				0
Total revenues			0				0
Operating expenses:
Acquisition related			0				(23,000)
Merger and other non-routine transactions			(1,612,000)				(16,341,000)
Property operating			(14,000)				(14,000)
Management fees to affiliate			0				12,493,000
General and administrative			7,458,000				17,655,000
Equity-based compensation			(7,180,000)				68,000
Depreciation and amortization			(276,000)				(313,000)
Operating fees to affiliate			0				0
Impairment of real estate			2,074,000				2,074,000
Total operating expenses			450,000				4,021,000
Operating income			(450,000)				(4,021,000)
Other (expense) income:
Interest expense			0				(585,000)
Loss on contingent value rights							0
Income from investment securities			0				0
Gain (loss) on sale of investment securities			0				0
Loss on derivative instruments							(10,000)
Other income, net			47,000				8,000
Total other expenses, net			37,000				(587,000)
Loss from continuing operations			(413,000)				(4,608,000)
Net (gain) loss from continuing operations attributable to non-controlling interests			2,923,000				6,741,000
Net loss from continuing operations attributable to stockholders			2,514,000				2,133,000
Discontinued operations:
Net income (loss) from operations of held for sale properties			0				0
(Loss) gain on held for sale properties			0				(14,000)
Net income (loss) from discontinued operations			0				(14,000)
Net (loss) income from discontinued operations attributable to non-controlling interests			5,000				9,000
Net income (loss) from discontinued operations attributable to stockholders			5,000				(5,000)
Net loss			(413,000)				(4,622,000)
Net (income) loss attributable to non-controlling interests			2,928,000				6,750,000
Net loss attributable to stockholders			2,515,000				2,128,000
Basic and diluted net loss per share from continuing operations attributable to common stockholders			$ 0.00				$ 0.00
Basic and diluted net loss per share attributable to common stockholders			$ 0.00				$ 0.00
Error Corrections [Member] | Adjustments [Member]
Operating expenses:
Equity-based compensation							$ (11,510,000)

[1] For discussion on the restatement adjustments, see Note 2 - Restatement of Previously Issued Consolidated Financial Statements.

[2] For discussion of the restatement adjustments, see Note 2 - Restatement of Previously Issued Consolidated Financial Statements.

[3] Includes $1.7 million to affiliates for the nine months ended September 30, 2014, and $10.1 million and $36.9 million to affiliates for the three and nine months ended September 30, 2013, respectively.

[4] Includes $137.8 million to affiliates for the nine months ended September 30, 2014, and $2.3 million and $109.2 million to affiliates for the three and nine months ended September 30, 2013, respectively.

[5] Includes $0.1 million and $16.1 million to affiliates for the three and nine months ended September 30, 2014, respectively, and $7.0 million and $16.3 million to affiliates for the three and nine months ended September 30, 2013, respectively.

[6] Certain line items have been consolidated from the original presentation in the Quarterly Report on Form 10-Q filing for the three and nine month period ended September 30, 2013.

[7] Certain line items have been consolidated from the original presentation in the Quarterly Report on Form 10-Q filing for the nine month period ended September 30, 2013.

[8] These financial statements have been recast in applying the carryover basis of accounting to include ARCT IV.