Restated Consolidated Statement of Cash Flows (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net loss	$ (507,815,000)	[1]	$ (42,237,000)	[1]	$ (4,804,000)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Issuance of OP Units for the ARCT III Merger	107,771,000	[1]	0	[1]	0
Depreciation	238,307,000	[2]
Amortization of intangible lease assets	0	[2]
Amortization of deferred costs	0	[2]
Amortization of above- and below-market lease asset	0	[2]
Amortization of discounts and premiums	0	[2]
Loss on held for sale properties	0	[1],[3],[4]	600,000	[1]	815,000
Impairment of real estate	3,346,000	[1],[5],[6]	0	[1]	0
Equity-based compensation	100,261,000	[1]	1,230,000	[1]	225,000
Unrealized gain on derivative instruments	(1,739,000)	[1]	0	[1]	0
Loss on sale of investments, net	2,206,000	[1]	0	[1]	0
Loss in extinguishment of Series C Stock	13,749,000	[1]	0	[1]	0
Changes in assets and liabilities:
Investment in direct financing leases	2,505,000	[1]	0	[1]	0
Prepaid expenses and other assets	(19,851,000)	[1]	(5,089,000)	[1]	(546,000)
Accounts payable and accrued expenses	20,789,000	[1]	8,277,000	[1]	843,000
Deferred rent and other liabilities	8,555,000	[1]	3,507,000	[1]	887,000
Due to affiliates	43,834,000	[1],[7]	0	[1]	0
Net cash provided by (used in) operating activities	11,918,000	[1]	9,440,000	[1]	(257,000)
Cash flows from investing activities:
Investments in real estate and other assets	(3,520,412,000)	[1],[8]	(1,659,536,000)	[1]	(89,981,000)
Acquisition of a real estate business, net of cash acquired of $41,779	(878,898,000)	[1]	0	[1]	0
Investment in direct financing leases	(68,617,000)	[1]	0	[1]	0
Capital expenditures	(9,755,000)	[1]	(54,000)	[1]	0
Principal repayments received from borrowers	442,000	[1]	0	[1]	0
Purchase of assets from Manager	(543,000)	[1],[9]	0	[1]	0
Deposits for real estate investments	(101,887,000)	[1]	(638,000)	[1]	0
Purchases of investment securities	(81,590,000)	[1]	(41,747,000)	[1]	0
Proceeds from sale of investment securities	119,542,000	[1]	0	[1]	0
Net cash used in investing activities	(4,541,718,000)	[1]	(1,701,422,000)	[1]	(89,981,000)
Cash flows from financing activities:
Proceeds from mortgage notes payable	6,924,000	[1]	229,798,000	[1]	21,470,000
Payments on mortgage notes payable	(5,711,000)	[1]	0	[1]	0
Payments on other debt	(9,368,000)	[1]	0	[1]	0
Payments on senior secured revolving credit facility	(124,604,000)	[1]	(122,000)	[1]	(11,159,000)
Proceeds from senior corporate credit facility	1,889,800,000	[1]	0	[1]	0
Payments on senior corporate credit facility	(830,000,000)	[1]	0	[1]	0
Proceeds from secured credit facility	789,000,000	[1]	0	[1]	0
Payments of deferred financing costs	(101,196,000)	[1]	(13,974,000)	[1]	(3,108,000)
Proceeds from issuance of convertible debt	967,786,000	[1]	0	[1]	0
Common stock repurchases	(359,193,000)	[1]	(1,534,000)	[1]	0
Cash payment on settlement of Series C Stock	(441,353,000)	[1]	0	[1]	0
Proceeds from issuance of common stock	2,158,486,000	[1]	1,909,520,000	[1]	122,993,000
Payments of offering costs and fees related to stock issuances	(165,327,000)	[1]	(218,108,000)	[1]	(20,884,000)
Consideration to Former Manager for internalization	0
Contributions from non-controlling interest holders	30,861,000	[1]	7,375,000	[1]	0
Distributions to non-controlling interest holders	(8,219,000)	[1]	(663,000)	[1]	(68,000)
Distributions paid	(234,897,000)	[1]	(37,673,000)	[1]	(1,743,000)
Advances from affiliates, net	(376,000)	[1]	396,000	[1]	0
Change in restricted cash	(5,654,000)
Net cash provided by financing activities	4,289,950,000	[1]	1,965,226,000	[1]	109,569,000
Net change in cash and cash equivalents	(239,850,000)	[1]	273,244,000	[1]	19,331,000
Cash and cash equivalents, beginning of period	292,575,000	[1]	19,331,000	[1]	0
Cash and cash equivalents, end of period	52,725,000	[1]	292,575,000	[1]	19,331,000	[1]
Common Class C [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	445,000,000	[1]	0	[1]	0
Series D preferred stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	287,991,000	[1]	0	[1]	0
As Previously Reported [Member]
Net loss	(480,456,000)	[10]	(42,237,000)	[11]
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Issuance of OP Units for the ARCT III Merger	108,247,000	[10]
Depreciation	162,027,000	[10],[2]
Amortization of intangible lease assets	49,345,000	[10],[2]
Amortization of deferred costs	26,895,000	[10],[2]
Amortization of above- and below-market lease asset	(176,000)	[10],[2]
Amortization of discounts and premiums	(1,700,000)	[10],[2]
Loss on held for sale properties	(14,000)	[10],[3],[4]
Impairment of real estate	0	[10],[5],[6]
Equity-based compensation	43,565,000	[10]
Unrealized gain on derivative instruments	(1,739,000)	[10]
Loss on sale of investments, net	2,206,000	[10]
Loss in extinguishment of Series C Stock	13,749,000	[10]
Changes in assets and liabilities:
Investment in direct financing leases	2,505,000	[10]
Prepaid expenses and other assets	(20,406,000)	[10]
Accounts payable and accrued expenses	100,166,000	[10]
Deferred rent and other liabilities	8,555,000	[10]
Due to affiliates	0	[10],[7]
Net cash provided by (used in) operating activities	12,769,000	[10]
Cash flows from investing activities:
Investments in real estate and other assets	(3,520,412,000)	[10]
Acquisition of a real estate business, net of cash acquired of $41,779	(878,898,000)	[10]
Investment in direct financing leases	(68,617,000)	[10]
Capital expenditures	(9,755,000)	[10]
Principal repayments received from borrowers	442,000	[10]
Purchase of assets from Manager	(1,584,000)	[10],[9]
Deposits for real estate investments	(101,887,000)	[10]
Purchases of investment securities	(81,590,000)	[10]
Proceeds from sale of investment securities	119,542,000	[10]
Net cash used in investing activities	(4,542,759,000)	[10]
Cash flows from financing activities:
Proceeds from mortgage notes payable	6,924,000	[10]
Payments on mortgage notes payable	(5,711,000)	[10]
Payments on other debt	(9,368,000)	[10]
Payments on senior secured revolving credit facility	(124,604,000)	[10]
Proceeds from senior corporate credit facility	1,889,800,000	[10]
Payments on senior corporate credit facility	(830,000,000)	[10]
Proceeds from secured credit facility	789,000,000	[10]
Payments of deferred financing costs	(95,268,000)	[10]
Proceeds from issuance of convertible debt	967,786,000	[10]
Common stock repurchases	(359,193,000)	[10]
Cash payment on settlement of Series C Stock	(441,353,000)	[10]
Proceeds from issuance of common stock	2,158,486,000	[10]
Payments of offering costs and fees related to stock issuances	(165,327,000)	[10]
Consideration to Former Manager for internalization	(5,738,000)	[10]
Contributions from non-controlling interest holders	30,861,000	[10]
Distributions to non-controlling interest holders	(8,219,000)	[10]
Distributions paid	(234,897,000)	[10]
Advances from affiliates, net	(376,000)	[10]
Change in restricted cash	(5,654,000)	[10]
Net cash provided by financing activities	4,290,140,000	[10]
Net change in cash and cash equivalents	(239,850,000)	[10]
Cash and cash equivalents, beginning of period	292,575,000	[10]
Cash and cash equivalents, end of period	52,725,000	[10]	292,575,000	[10]
As Previously Reported [Member] | Common Class C [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	445,000,000	[10]
As Previously Reported [Member] | Series D preferred stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	287,991,000	[10]
Reclassifications And Immaterial Adjustments [Member]
Net loss	0
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Issuance of OP Units for the ARCT III Merger	0
Depreciation	74,364,000	[2]
Amortization of intangible lease assets	(49,345,000)	[2]
Amortization of deferred costs	(26,895,000)	[2]
Amortization of above- and below-market lease asset	176,000	[2]
Amortization of discounts and premiums	1,700,000	[2]
Loss on held for sale properties	0	[3],[4]
Impairment of real estate	0	[5],[6]
Equity-based compensation	0
Unrealized gain on derivative instruments	0
Loss on sale of investments, net	0
Loss in extinguishment of Series C Stock	0
Changes in assets and liabilities:
Investment in direct financing leases	0
Prepaid expenses and other assets	0
Accounts payable and accrued expenses	0
Deferred rent and other liabilities	0
Due to affiliates	0	[7]
Net cash provided by (used in) operating activities	0
Cash flows from investing activities:
Investments in real estate and other assets	0
Acquisition of a real estate business, net of cash acquired of $41,779	0
Investment in direct financing leases	0
Capital expenditures	0
Principal repayments received from borrowers	0
Purchase of assets from Manager	0	[9]
Deposits for real estate investments	0
Purchases of investment securities	0
Proceeds from sale of investment securities	0
Net cash used in investing activities	0
Cash flows from financing activities:
Proceeds from mortgage notes payable	0
Payments on mortgage notes payable	0
Payments on other debt	0
Payments on senior secured revolving credit facility	0
Proceeds from senior corporate credit facility	0
Payments on senior corporate credit facility	0
Proceeds from secured credit facility	0
Payments of deferred financing costs	0
Proceeds from issuance of convertible debt	0
Common stock repurchases	0
Cash payment on settlement of Series C Stock	0
Proceeds from issuance of common stock	0
Payments of offering costs and fees related to stock issuances	0
Consideration to Former Manager for internalization	0
Contributions from non-controlling interest holders	0
Distributions to non-controlling interest holders	0
Distributions paid	0
Advances from affiliates, net	0
Change in restricted cash	0
Net cash provided by financing activities	0
Net change in cash and cash equivalents	0
Cash and cash equivalents, beginning of period	0
Cash and cash equivalents, end of period	0
Reclassifications And Immaterial Adjustments [Member] | Common Class C [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	0
Reclassifications And Immaterial Adjustments [Member] | Series D preferred stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	0
Error Corrections [Member]
Net loss	(27,359,000)		0
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Issuance of OP Units for the ARCT III Merger	(476,000)
Depreciation	1,916,000	[2]
Amortization of intangible lease assets	0	[2]
Amortization of deferred costs	0	[2]
Amortization of above- and below-market lease asset	0	[2]
Amortization of discounts and premiums	0	[2]
Loss on held for sale properties	14,000	[3],[4]
Impairment of real estate	3,346,000	[5],[6]
Equity-based compensation	56,696,000
Unrealized gain on derivative instruments	0
Loss on sale of investments, net	0
Loss in extinguishment of Series C Stock	0
Changes in assets and liabilities:
Investment in direct financing leases	0
Prepaid expenses and other assets	555,000
Accounts payable and accrued expenses	(79,377,000)
Deferred rent and other liabilities	0
Due to affiliates	43,834,000	[7]
Net cash provided by (used in) operating activities	(851,000)
Cash flows from investing activities:
Investments in real estate and other assets	0
Acquisition of a real estate business, net of cash acquired of $41,779	0
Investment in direct financing leases	0
Capital expenditures	0
Principal repayments received from borrowers	0
Purchase of assets from Manager	1,041,000	[9]
Deposits for real estate investments	0
Purchases of investment securities	0
Proceeds from sale of investment securities	0
Net cash used in investing activities	1,041,000
Cash flows from financing activities:
Proceeds from mortgage notes payable	0
Payments on mortgage notes payable	0
Payments on other debt	0
Payments on senior secured revolving credit facility	0
Proceeds from senior corporate credit facility	0
Payments on senior corporate credit facility	0
Proceeds from secured credit facility	0
Payments of deferred financing costs	(5,928,000)
Proceeds from issuance of convertible debt	0
Common stock repurchases	0
Cash payment on settlement of Series C Stock	0
Proceeds from issuance of common stock	0
Payments of offering costs and fees related to stock issuances	0
Consideration to Former Manager for internalization	5,738,000
Contributions from non-controlling interest holders	0
Distributions to non-controlling interest holders	0
Distributions paid	0
Advances from affiliates, net	0
Change in restricted cash	0
Net cash provided by financing activities	(190,000)
Net change in cash and cash equivalents	0
Cash and cash equivalents, beginning of period	0
Cash and cash equivalents, end of period	0		0
Error Corrections [Member] | Common Class C [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	0
Error Corrections [Member] | Series D preferred stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Stock	$ 0

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

[2] These five depreciation and amortization line items have been consolidated into one line item named depreciation and amortization in the accompanying consolidated statements of cash flows.

[3] This line item caption has been updated to loss on held for sale properties in the accompanying consolidated statements of operations.

[4] This line item caption has been updated to loss on held for sale properties in the accompanying consolidated statements of cash flows.

[5] As disclosed above, this line item has been added and is included in the accompanying consolidated statements of operations.

[6] As disclosed above, this line item has been added and is included in the accompanying consolidated statements of cash flows.

[7] This line item caption has been added and is included in the accompanying consolidated statements of cash flows.

[8] Excludes 50 properties comprised of $66.1 million of net investments subject to direct financing leases.

[9] This line item caption has been updated to investments in other assets in the accompanying consolidated statements of cash flows.

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

[11] These financial figures have been recast in applying the carryover basis of accounting to include the effects of the merger with ARCT IV.