Welltower (WELL) 10-Q 4 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	3 Months Ended
	Mar. 31, 2018	Apr. 27, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	WELLTOWER INC. /DE/
Entity Central Index Key	766,704
Document Type	10-Q
Document Period End date	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 27,562,002,967
Entity Common Stock Shares Outstanding		371,981,518

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018		Dec. 31, 2017
Real property owned:
Land and land improvements	$ 2,793,671		$ 2,734,467
Buildings and improvements	25,672,558		25,373,117
Acquired lease intangibles	1,548,621		1,502,471
Real property held for sale, net of accumulated depreciation	368,249		734,147
Construction in progress	180,984		237,746
Gross real property owned	30,564,083		30,581,948
Less accumulated depreciation and amortization	(4,990,780)		(4,838,370)
Net real property owned	25,573,303		25,743,578
Real estate loans receivable:
Real estate loans receivable	436,194		495,871
Allowance for losses on loans receivable	(68,372)		(68,372)
Net real estate loans receivable	367,822		427,499
Net real estate investments	25,941,125		26,171,077
Other assets:
Investments in unconsolidated entities	440,424		445,585
Goodwill	68,321		68,321
Cash and cash equivalents	202,824		243,777
Restricted cash	61,295		65,526
Straight-line rent receivable	406,260		389,168
Receivables and other assets	626,410		560,991
Total other assets	1,805,534		1,773,368
Total assets	27,746,659		27,944,445
Liabilities:
Borrowings under primary unsecured credit facilities, Carrying Value	865,000	[1]	719,000
Senior unsecured notes	7,924,340		8,331,722
Secured debt	2,488,652		2,608,976
Capital lease obligations	71,848		72,238
Accrued expenses and other liabilities	948,618		911,863
Total liabilities	12,298,458		12,643,799
Redeemable noncontrolling interests	388,875		375,194
Equity:
Preferred stock	718,498		718,503
Common stock	372,729		372,449
Capital in excess of par value	17,667,674		17,662,681
Treasury stock	(68,696)		(64,559)
Cumulative net income	5,765,927		5,316,580
Cumulative dividends	(9,807,114)		(9,471,712)
Accumulated other comprehensive income (loss)	(91,253)		(111,465)
Other equity	670		670
Total Welltower Inc. stockholders' equity	14,558,435		14,423,147
Noncontrolling interests	500,891		502,305
Total equity	15,059,326		14,925,452
Total liabilities and equity	$ 27,746,659		$ 27,944,445
[1]	As of March 31, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Rental income	$ 343,369	$ 367,141
Resident fees and services	735,934	670,337
Interest income	14,648	20,748
Other income	3,014	4,072
Total revenues	1,096,965	1,062,298
Expenses:
Interest expense	122,775	118,597
Property operating expenses	556,465	510,169
Depreciation and amortization	228,201	228,276
General and administrative	33,705	31,101
Loss (gain) on derivatives and financial instruments, net	(7,173)	1,224
Loss (gain) on extinguishment of debt, net	11,707	31,356
Impairment of Asset	28,185	11,031
Other expenses	3,712	11,675
Total expenses	977,577	943,429
Income (loss) from continuing operations before income taxes and income from unconsolidated entities, total	119,388	118,869
Income tax expense	(1,588)	(2,245)
(Loss) income from unconsolidated entities	(2,429)	(23,106)
Income from continuing operations	115,371	93,518
Gain (loss) on real estate dispositions, net	338,184	244,092
Net income	453,555	337,610
Less: Preferred stock dividends	11,676	14,379
Preferred stock redemption charge	0	9,769
Less: Net income (loss) attributable to noncontrolling interests	4,208	823
Net income (loss) attributable to common stockholders	$ 437,671	$ 312,639
Average number of common shares outstanding:
Basic	371,426	362,534
Diluted	373,257	364,652
Basic:
Income (loss) from continuing operations attributable to common stockholders, including real estate dispositions	$ 0.31	$ 0.26
Net income (loss) attributable to common stockholders, total	1.18	0.86
Diluted:
Income (loss) from continuing operations attributable to common stockholders, including real estate dispositions	0.31	0.26
Net income (loss) attributable to common stockholders, total	1.17	0.86
Dividends declared and paid per common share	$ 0.87	$ 0.87

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 453,555	$ 337,610
Other comprehensive income (loss):
Unrecognized gain (loss) on equity investments		0	(10,569)
Foreign currency translation gain (loss)		16,326	5,713
Total other comprehensive income (loss)		16,326	(4,856)
Total comprehensive income (loss), total		469,881	332,754
Total comprehensive income (loss) attributable to noncontrolling interests	[1]	322	3,636
Comprehensive income (loss) attributable to controlling interests		$ 469,559	$ 329,118
[1]	Includes amounts attributable to redeemable noncontrolling interests.

Consolidated Statements of Equi

Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Capital in Excess of Par Value	Treasury Stock	Cumulative Net Income	Cumulative Dividends	Accumulated Other Comprehensive Income (Loss)	Other Equity	Noncontrolling Interests
Balances at beginning of period at Dec. 31, 2016	$ 15,281,472	$ 1,006,250	$ 363,071	$ 16,999,691	$ (54,741)	$ 4,803,575	$ (8,144,981)	$ (169,531)	$ 3,059	$ 475,079
Comprehensive income:
Net income (loss)	338,567					336,787				1,780
Other comprehensive income	(4,856)							(7,669)		2,813
Total comprehensive income	333,711
Increase in noncontrolling interests				932
Decrease in noncontrolling interests	(4,680)									(5,612)
Amounts related to stock incentive plans, net of forfeitures	(1,931)		336	6,903	(7,565)				(1,605)
Proceeds from issuance of common stock	118,984		1,780	117,204
Redemption of preferred stock	(287,509)	(287,500)		9,760		(9,769)
Option compensation expense	10								10
Cash dividends paid:
Common stock	(315,415)						(315,415)
Preferred Stock	(14,379)						(14,379)
Balances at end of period at Mar. 31, 2017	15,110,263	718,750	365,187	17,134,490	(62,306)	5,130,593	(8,474,775)	(177,200)	1,464	474,060
Balances at beginning of period at Dec. 31, 2017	14,925,452	718,503	372,449	17,662,681	(64,559)	5,316,580	(9,471,712)	(111,465)	670	502,305
Comprehensive income:
Net income (loss)	454,538					449,347				5,191
Other comprehensive income	16,326							20,212		(3,886)
Total comprehensive income	470,864
Decrease in noncontrolling interests	(15,876)			(13,157)						(2,719)
Amounts related to stock incentive plans, net of forfeitures	7,098		150	11,085	(4,137)				0
Proceeds from issuance of common stock	7,190		130	7,060
Conversion of preferred stock	0	(5)		5
Cash dividends paid:
Common stock	(323,726)						(323,726)
Preferred Stock	(11,676)						(11,676)
Balances at end of period at Mar. 31, 2018	$ 15,059,326	$ 718,498	$ 372,729	$ 17,667,674	$ (68,696)	$ 5,765,927	$ (9,807,114)	$ (91,253)	$ 670	$ 500,891

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net income (loss)		$ 453,555	$ 337,610
Adjustments to reconcile net income to net cash provided from (used in) operating activities:
Depreciation and amortization		228,201	228,276
Other amortization expenses		4,171	3,361
Asset Impairment Charges		28,185	11,031
Stock-based compensation expense		11,557	4,906
Loss (gain) on derivatives and financial instruments, net		(7,173)	1,224
Loss (gain) on extinguishment of debt, net		11,707	31,356
Income from unconsolidated entities		2,429	23,106
Rental income in excess of cash received		(21,406)	(18,141)
Amortization related to above (below) market leases, net		718	8
Net loss (gain) on sales of properties		(338,184)	(244,092)
Distributions by unconsolidated entities		0	474
Increase (decrease) in accrued expenses and other liabilities		(10,707)	19,478
Decrease (increase) in receivables and other assets		5,591	(13,071)
Net cash provided from (used in) operating activities		368,644	385,526
Investing activities
Cash disbursed for acquisitions		(405,609)	(102,356)
Cash disbursed for capital improvements to existing properties		(46,547)	(42,115)
Cash disbursed for construction in progress		(22,735)	(69,334)
Capitalized interest		(2,336)	(4,129)
Investment in real estate loans receivable		(27,547)	(25,375)
Other investments, net of payments		(49,279)	48,311
Principal collected on real estate loans receivable		90,731	8,792
Contributions to unconsolidated entities		(14,366)	(13,073)
Distributions by unconsolidated entities		14,880	24,161
Proceeds from (payments on) derivatives investing		(8,324)	8,218
Decrease (increase) in restricted cash		0	0
Proceeds from sales of real property		892,209	1,087,074
Net cash provided from (used in) investing activities		421,077	920,174
Financing activities
Net increase (decrease) under unsecured lines of credit arrangements		146,000	(123,000)
Payments to extinguish senior unsecured notes		(450,000)	0
Net proceeds from the issuance of secured debt		20,326	12,536
Payments on secured debt		(197,655)	(822,438)
Net proceeds from the issuance of common stock		7,214	119,651
Redemption of preferred stock		0	(287,500)
Decrease (increase) in deferred loan costs		(14,341)	(36,674)
Contributions by noncontrolling interests	[1]	5,734	2,667
Distributions to noncontrolling interests	[1]	(12,564)	(20,014)
Acquisitions of noncontrolling interests		0	(38)
Cash distributions to stockholders		(335,508)	(329,794)
Other financing activities		(4,555)	(8,022)
Net cash provided from (used in) financing activities		(835,349)	(1,492,626)
Effect of foreign currency translation on cash, cash equivalents and restricted cash		444	2,843
Increase (decrease) in cash and cash equivalents		(45,184)	(184,083)
Cash, cash equivalents and restricted cash at the beginning of period		309,303	607,220
Cash, cash equivalents and restricted cash at the end of period		264,119	423,137
Supplemental cash flow information:
Interest paid		104,246	109,438
Income taxes paid (received), net		$ (721)	$ 3,349
[1]	(1) Includes amounts attributable to redeemable noncontrolling interests.

Business

Business	3 Months Ended
	Mar. 31, 2018
Business [Abstract]
Business	1 . Business Welltower Inc., an S&P 500 company headquartered in Toledo, Ohio, is driving the transformation of health care infrastructure. The company invests with leading seniors housing operators, post-acute providers and health systems to fund the real estate and infrastructure needed to scale innovative care delivery models and improve people’s wellness and overall health care experience. Welltower™, a real estate investment trust (“REIT”), owns interests in properties concentrated in maj or, high-growth markets in the United States, Canada and the United Kingdom, consisting of seniors housing and post-acute communities and outpatient medical properties .

Accounting Policies and Related

Accounting Policies and Related Matters	3 Months Ended
	Mar. 31, 2018
Accounting Policies and Related Matters [Abstract]
Accounting Policies and Related Matters	2 . Accounting Policies and Related Matters Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments ( such as normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2018 are not necessarily an indication of the results that may be expect ed for the year ending December 31, 2018 . For further information, refer to the financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017 . New Accounting Standards We adopted the followin g accounting standards, each of which did not have a material impact on our consolidated financial statements: In 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts wi th Customers (ASC 606),” which is a comprehensive new revenue recognition model that requires revenue to be recognized in a manner to depict the transfer of goods or services to a customer at an amount that reflects the consideration expected to be receive d in exchange for those goods or services. We adopted ASC 606 on January 1, 2018 using the modified retrospective method of adoption . This guidance did not have a significant impact on our consolidated financial statements. We have evaluated our various revenue streams to identify whether they would be subject to the provisions of ASC 606 and any differences in timing, measurement or presentation of revenue recognition. A significant source of our revenue is generated through leasing arrangements, which are specifically excluded from ASC 606. Management contracts are present in our seniors ho using operating and outpatient medical segments and represent agreements to provide asset and property management, leasing, marketing and other services. Under ASC 606, the pattern and timing of recognition of income from these contracts is consistent wit h the prior accounting model. In 2017, the FASB issued ASU No. 2017-05, “Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sale s of Nonfinancial Assets.” The standard clarifies that a financial asset is within the scope of Subtopic 610-20 if it meets the definition of an in substance nonfinancial asset. The standard also defines the term “ in substance nonfinancial asset” and clarifies t hat an entity should identify each distinct nonfinancial asset or in substance nonfinancial asset promised to a counterparty and derecognize each asset when a counterparty obtains control over it. We adopted Subtopic 610-20 using a modified retrospective approach on January 1, 2018. In 2016, the FASB issued ASU No. 2016-01, “Financial Instruments – Overall: Recognition and Measurement of Financial Assets and Financial Liabilities,” which requires entities to measure their investments at fair value and reco gnize any changes in fair value in net income unless the investments qualify for the new practicability exception. The practicability exception is available for equity investments that do not have readily determinable fair values. This standard requires u s to recognize gains and losses from changes in the fair value of our available-for-sale equity securities through the consolidated statement of comprehensive income rather than through accumulated other comprehensive income. During the three months ended March 31, 2018, we recognized a gain of $7,173,000 in loss (gain) on derivatives and financial instruments, net on the consolidated statement of comprehensive income. There was no adjustment to accumulated other comprehensive income upon adoption at Janua ry 1, 2018 as accumulated losses were recognized as other-than-temporary impairment during the year ended December 31, 2017. During the three months ended December 31, 2017, we adopted ASU No. 2016-18, “Restricted Cash,” and ASU No . 2016-15, “Classification of Certain Cash Receipts and Cash Payments.” ASU No. 2016-18 requires an entity to reconcile and explain the period over period change in total cash, cash equivalents and restricted cash within its consolidated statement of cash flows and ASU 2016-15 provides guidance clarifying how certain cash receipts and cash payments should be classified. We adopted these accounting standards retrospectively and, accordingly, certain line items in the consolidated statement of cash flows ha ve been reclassified to conform to the current presentation. The following table summarizes the change in cash flows as reported and as previously reported prior to the adoption of these standards for the three months ended March 31, 2017 (in thousa nds): As Previously As Reported Reported Cash disbursed for acquisitions $ (102,356) $ (102,356) Decrease (increase) in restricted cash - 145,065 Net cash provided from (used in) investing activities 920,174 1,065,239 Increase (decrease) in balance (1) (184,083) (39,018) Balance at beginning of period (1) 607,220 419,378 Balance at end of period (1) 423,137 380,360 (1) Amounts in As Reported column include cash and cash equivalents and restricted cash as required. Amounts in the As Previously Reported column reflect only cash and cash equivalents. The following ASUs have been issued but not yet adopted: In 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842),” which requires lessees to recognize assets and liabilities on their consolidated balance sheet related to the rights and obligations created by most leases, while continuing to recognize expenses on their consolidated statements of comprehensive income over the lease term. It will also require disclosures designed to give financial statement users information regarding amou nt, timing, and uncertainty of cash flows arising from leases. The FASB issued an Exposure Draft in January 2018 proposing to amend ASU 2016-02, which would provide lessors with a practical expedient, by class of underlying assets, to not separate non-lea se components from the related lease components and, instead, to account for those components as a single lease component, if certain criteria are met. ASU 2016-02 and the Exposure Draft are effective for us beginning January 1, 2019, with early adoption permitted. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the consolidated financial statements. We are currently evaluating the impact of this guidance on our consolidated financial statements from both the lessee and lessor perspective. We believe that adoption will likely have a material impact to our consolidated financial statements for the recognition of certain operating leases as ri ght-of-use assets and lease liabilities and related amortizations. We expect to utilize the practical expedients proposed in the Exposure Draft as part of our adoption of this guidance. In 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Los ses on Financial Instruments.” This standard requires a new forward-looking “expected loss” model to be used for receivables, held-to-maturity debt, loans, and other instruments. ASU 2016-13 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, and early adoption is permitted for fiscal years beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. In August 2017, th e FASB issued ASU 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities,” which expands and refines hedge accounting for both nonfinancial and financial risk components and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. It also includes certain targeted improvements to simplify the application of current guidance related to hedge accounting. The standard is effective for fiscal years, a nd interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. We expect to adopt this guidance during the three months ended June 30, 2018 and are currently evaluating the impact th e effects this standard will have on our consolidated financial statements .

Real Property Acquisitions and

Real Property Acquisitions and Development	3 Months Ended
	Mar. 31, 2018
Real Property Acquisitions and Development [Abstract]
Real Property Acquisitions and Development	3 . Real Property Acquisition s and Development The total purchase price for all properties acquired has been allocated to the tangible and identifiable intangible assets, liabilities and noncontrolling interests based upon their relative fair values in accordance with our accounting policies. The results of operations for these acquisitions have been included in our consolidated results of operations since the date of acquisition and are a component of the appropriate segments. Transacti on costs primarily represent costs incurred with acquisitions, including due diligence costs, fees for legal and valuation services and termination of pre-existing relationships computed based on the fair value of the assets acquired, lease termination fee s and other acquisition-related costs. T ransaction costs related to asset acquisitions are capitalized as a component of purchase price and all other non-capitalizable costs are reflected in “Ot her Expenses” on our Consolidated Statements of Comprehensive Income. Certain of our subsidiaries’ functional currencies are the local currencies of their respective countries. See Note 2 to the financial statements included in our Annual Report on Form 10 -K for the year ended December 31, 2017 for information regarding our foreign currency policies. Triple-n et Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 1,691 $ 4,017 Buildings and improvements 235 37,241 Total assets acquired 1,926 41,258 Accrued expenses and other liabilities (6) - Total liabilities assumed (6) - Cash disbursed for acquisitions (1) 1,920 41,258 Construction in progress additions 15,850 46,754 Less: Capitalized interest (847) (2,028) Foreign currency translation - (164) Cash disbursed for construction in progress 15,003 44,562 Capital improvements to existing properties 2,351 10,495 Total cash invested in real property, net of cash acquired $ 19,274 $ 96,315 (1) Primarily reprsents land acquired on an existing property during the three months ended March 31, 2018. Seniors Housing Operating Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 35,193 $ 4,304 Building and improvements 372,562 44,075 Acquired lease intangibles 48,805 1,741 Receivables and other assets 265 74 Total assets acquired (1) 456,825 50,194 Secured debt (89,973) - Accrued expenses and other liabilities (12,808) (2,755) Total liabilities assumed (102,781) (2,755) Noncontrolling interests (5,618) (647) Non-cash acquisition related activity (2) - (14,148) Cash disbursed for acquisitions 348,426 32,644 Construction in progress additions 10,562 8,062 Less: Capitalized interest (891) (1,707) Foreign currency translation (5,032) 691 Cash disbursed for construction in progress 4,639 7,046 Capital improvements to existing properties 31,325 24,254 Total cash invested in real property, net of cash acquired $ 384,390 $ 63,944 (1) Excludes $2,155,000 and $400,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018 and 2017, respectively. (2) Includes $6,349,000 related to the acquisition of assets previously financed as real estate loans receivable and $7,799,000 previously financed as an investment in an unconsolidated entity during the three months ended March 31, 2017. Outpatient Medical Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 7,369 $ 2,895 Buildings and improvements 42,673 23,310 Acquired lease intangibles 5,852 3,496 Receivables and other assets 1 3 Total assets acquired (1) 55,895 29,704 Accrued expenses and other liabilities (632) (1,250) Total liabilities assumed (632) (1,250) Cash disbursed for acquisitions 55,263 28,454 Construction in progress additions 2,803 14,921 Less: Capitalized interest (598) (717) Accruals (2) 888 3,522 Cash disbursed for construction in progress 3,093 17,726 Capital improvements to existing properties 12,871 7,366 Total cash invested in real property $ 71,227 $ 53,546 (1) Excludes $1,950,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018. (2) Represents non-cash accruals for amounts to be paid in future periods for properties that converted, off-set by amounts paid in the current period. Construction Activity The following is a summary of the construction projects that were placed into service and began generating revenues during the periods presented (in thousands) : Three Months Ended March 31, 2018 March 31, 2017 Development projects: Triple-net $ 49,759 $ 157,460 Seniors housing operating 36,218 3,634 Outpatient medical - 25,910 Total development projects 85,977 187,004 Total construction in progress conversions $ 85,977 $ 187,004

Real Estate Intangibles

Real Estate Intangibles	3 Months Ended
	Mar. 31, 2018
Real Estate Intangibles [Abstract]
Real Estate Intangibles	4 . Real Estate Intangibles The following is a summary of our real estate intangibles , excluding those classified as held for sale, as of the dates indicated (dollars in thousands): March 31, 2018 December 31, 2017 Assets: In place lease intangibles $ 1,395,920 $ 1,352,139 Above market tenant leases 58,402 58,443 Below market ground leases 59,030 58,784 Lease commissions 35,269 33,105 Gross historical cost 1,548,621 1,502,471 Accumulated amortization (1,149,223) (1,125,437) Net book value $ 399,398 $ 377,034 Weighted-average amortization period in years 14.4 15.1 Liabilities: Below market tenant leases $ 71,706 $ 60,430 Above market ground leases 8,540 8,540 Gross historical cost 80,246 68,970 Accumulated amortization (40,400) (39,629) Net book value $ 39,846 $ 29,341 Weighted-average amortization period in years 16.0 20.1 The following is a summary of real estate intangible amortization for the periods presented (in thousands): Three Months Ended March 31, 2018 2017 Rental income related to above/below market tenant leases, net $ (351) $ 304 Property operating expenses related to above/below market ground leases, net 367 (312) Depreciation and amortization related to in place lease intangibles and lease commissions (32,261) (39,302) The future estimated aggregate amortization of intangible assets and liabilities is as follows for the periods presented (in thousands): Assets Liabilities 2018 $ 94,521 $ 4,470 2019 74,771 5,582 2020 47,871 5,085 2021 20,985 4,597 2022 17,770 4,132 Thereafter 143,480 15,980 Total $ 399,398 $ 39,846

Dispositions, Assets Held for S

Dispositions, Assets Held for Sale and Discontinued Operations	3 Months Ended
	Mar. 31, 2018
Disclosure Dispositions, Assets Held for Sale and Discontinued Operations [Abstract]
Dispositions, Assets Held for Sale and Discontinued Operations	5 . Dispositions, Assets Held for Sale and Discontinued Operations We periodically sell properties for various reasons, including favorable market conditions, the exercise of tenant purchase options or reduction of concentrations (e.g., property type, relationship or geography ). At March 31, 2018, 36 triple-net, seven seniors housing operating and two outpatient medical properties with an aggregate real estate balance of $368,249,000 were classified as held for sale. During the three months ended March 31, 2018 , we recorded impairment charges of $28,185,000 on certain held for sale seniors housing operating , triple-net and outpatient medical properties for which the carrying values exceeded the fair values, less estimated cost s to sell if applicable. The following is a summary of our real property disposition activity for the periods presented (in thousands): Three Months Ended March 31, 2018 March 31, 2017 Real estate dispositions: Triple-net $ 323,667 $ 808,204 Seniors housing operating 2,200 13,845 Outpatient medical 223,069 - Total dispositions 548,936 822,049 Gain (loss) on real estate dispositions, net 338,184 244,092 Net other assets/liabilities disposed 5,089 20,933 Proceeds from real estate dispositions $ 892,209 $ 1,087,074 Dispositions and Assets Held for Sale Pursuant to our adoption of ASU No. 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity”, operating results attributable to properties sold subsequent to or classified as held for sale after January 1, 2014 and which do not meet the definition of discontinued operations are no longer reclassified on our Consolidated S tatements of Comprehensive Income. The following represents the activity related to these properties for the periods presented (in thousands): Three Months Ended March 31, 2018 2017 Revenues: Rental income $ 13,886 $ 43,787 Expenses: Interest expense 127 2,707 Property operating expenses 7,256 8,521 Provision for depreciation 1,741 9,813 Total expenses 9,124 21,041 Income (loss) from real estate dispositions, net $ 4,762 $ 22,746

Real Estate Loans Receivable

Real Estate Loans Receivable	3 Months Ended
	Mar. 31, 2018
Real Estate Loans Receivable [Abstract]
Real Estate Loans Receivable	6 . Real Estate Loans Receivable Please see Note 2 to the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017 for discussion of our accounting policies for real estate loans receivable and related interest income. The following is a summary of our real estate loan activity for the periods presented (in thousands): Three Months Ended March 31, 2018 March 31, 2017 Senior Senior Housing Outpatient Housing Outpatient Triple-net Operating Medical Totals Triple-net Operating Medical Totals Advances on real estate loans receivable: Investments in new loans $ 1,172 $ 11,806 $ 2,458 $ 15,436 $ 7,828 $ - $ - $ 7,828 Draws on existing loans 12,111 - - 12,111 17,547 - - 17,547 Net cash advances on real estate loans 13,283 11,806 2,458 27,547 25,375 - - 25,375 Receipts on real estate loans receivable: Loan payoffs 58,557 - - 58,557 14,474 - 60,500 74,974 Principal payments on loans 32,174 - - 32,174 667 - - 667 Sub-total 90,731 - - 90,731 15,141 - 60,500 75,641 Less: Non-cash activity (1) - - - - (6,349) - (60,500) (66,849) Net cash receipts on real estate loans 90,731 - - 90,731 8,792 - - 8,792 Net cash advances (receipts) on real estate loans $ (77,448) $ 11,806 $ 2,458 $ (63,184) $ 16,583 $ - $ - $ 16,583 (1) Triple-net represents acquisitions of assets previously financed as real estate loans. Please see Note 3 for additional information. Outpatient medical represents a deed in lieu of foreclosure on a previously financed first mortgage property. In 2016 , we restructured real estate loans with Genesis Health C are and recorded a loan loss charge in the amount of $6,935,000 on one of the loans as the present value of expected future cash flows was less than the carrying value of the loan. In 2017, we recorded an additional loan loss charge of $62,966,000 relating to real estate loans with Genesis HealthCare based on an estimation of expected future cash flows discounted at the effective interest rate of the loans. A t March 31, 2018 , the allowance for loan losses totals $ 68,372,000 and is deemed to be sufficient to absorb expected losses related to these loans . At March 31, 2018 , we had no real estate loans with outstanding balances on non-accrual status and recorded no provision for loan losses during the three m onths ended March 31, 2018 . Three Months Ended March 31, 2018 March 31, 2017 Balance of impaired loans at end of period $ 214,896 $ 317,049 Allowance for loan losses 68,372 6,196 Balance of impaired loans not reserved $ 146,524 $ 310,853 Average impaired loans for the period $ 265,973 $ 340,920 Interest recognized on impaired loans (1) 5,327 8,243 (1) Represents cash interest recognized in the period since loans were identified as impaired.

Investments in Unconsolidated E

Investments in Unconsolidated Entities	3 Months Ended
	Mar. 31, 2018
Investments In Unconsolidated Entities [Abstract]
Investments in Unconsolidated Entities	7 . Investments in Unconsolidated Entities We participate in a number of joint ventures, which generally invest in seniors housing and health care real estate. The results of operations for these entities have been included in our consolidated results of operations from the date of acquisition by the joint ventures and are reflected in our Consolidated Statements of Comprehensive Income as income or loss from unconsolidated entities. The following is a summary of our investments in unconsolida ted entities (dollars in thousands): Percentage Ownership (1) March 31, 2018 December 31, 2017 Triple-net 10% to 49% $ 22,440 $ 22,856 Seniors housing operating 10% to 50% 338,154 352,430 Outpatient medical 43% 79,830 70,299 Total $ 440,424 $ 445,585 (1) Excludes in-substance real estate investments. At March 31, 2018 , the aggregate unamortized basis difference of our joint venture investments of $ 108,549 ,000 is primarily attributable to the difference between the amount for which we purchase our interest in the entity, including transaction costs, and the historical carrying value of the net assets of the joint venture. This difference is being amortized over the remaini ng useful life of the related properties and included in the reported amount of income from unconsolidated entities.

Credit Concentration

Credit Concentration	3 Months Ended
	Mar. 31, 2018
Customer Concentration [Abstract]
Credit Concentration	8 . Credit Concentration We use consolidated net operating income (“NOI”) as our credit concentration metric. See Note 17 for additional information and reconciliation. The following table summarizes certain information about our credit concentration for the three months ended March 31, 2018 , excluding our share of NOI in unconsolidated entities (dollars in thousands): Number of Total Percent of Concentration by relationship: (1) Properties NOI NOI (2) Sunrise Senior Living (3) 160 $ 79,838 15% Revera (3) 98 39,525 7% Brookdale Senior Living 137 36,865 7% Genesis HealthCare 86 34,773 6% Benchmark Senior Living 48 23,948 4% Remaining portfolio 728 325,551 61% Totals 1,257 $ 540,500 100% (1) Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments. (2) NOI with our top five relationships comprised 41% of total NOI for the year ended December 31, 2017. (3) Revera owns a controlling interest in Sunrise Senior Living.

Borrowings Under Credit Facilit

Borrowings Under Credit Facilities and Related Items	3 Months Ended
	Mar. 31, 2018
Borrowings Under Credit Facilities and Related Items [Abstract]
Borrowings Under Credit Facilities and Related Items	9 . Borrowings Under Credit Facilities and Related Items At March 31, 2018 , we had a primary unsecured credit facility with a consortium of 29 banks that includes a $3,000,000,000 unsecured revolving credit facility, a $500,000,000 unsecured term credit facility and a $250,000,000 Canadian-denominated unsecured term credit facility. We have an option, through an accordion feature, to upsize the unsecured revolving credit facility and the $500,000,000 unsecured term credit facility by up to an additional $1,000,000,000, in the aggregate, and the $250,000,000 Canadian-denominated unsecured term credit facility by up to an additional $250,000,000. The primary unsecured credit facility also allows us to borrow up to $1,000,000,000 in alternate cu rrencies (none outstanding at March 31, 2018 ). Borrowings under the unsecured revolving credit facility are subject to interest payable at the applicable margin over LIBOR interest rate ( 2.78% at March 31, 2018 ). The applicable margin is based on our debt ratings and was 0.90% at March 31, 2018 . In addition, we pay a facility fee quarterly to each bank based on the bank’s commitment amount. The facility fee depends on our debt ratings and was 0.15% at March 31, 2018 . The term credit facilities mature on May 13, 202 1. The revolving credit facility is scheduled to mature on May 13, 2020 and can be extended for two successive terms of six months each at our option. The following information relates to aggregate borrowings under the primary unsecured revolving cre dit facility for the periods presented (dollars in thousands): Three Months Ended March 31, 2018 2017 Balance outstanding at quarter end (1) $ 865,000 $ 522,000 Maximum amount outstanding at any month end $ 865,000 $ 1,010,000 Average amount outstanding (total of daily principal balances divided by days in period) $ 364,111 $ 796,356 Weighted average interest rate (actual interest expense divided by average borrowings outstanding) 2.72% 1.81% (1) As of March 31, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.

Senior Unsecured Notes and Secu

Senior Unsecured Notes and Secured Debt	3 Months Ended
	Mar. 31, 2018
Senior Unsecured Notes and Secured Debt [Abstract]
Senior Unsecured Notes and Secured Debt	10 . Senior Unsecured Notes and Secured Debt We may repurchase, redeem or refinance senior unsecured notes from time to time, taking advantage of favorable market conditions when available. We may purchase senior notes for cash through open market purchases, privately negotiated transactions, a tender offer or, in some cases, through the early redemption of such securities pursuant to their terms. The senior unsecured notes are redeemable at our option, at any time in whole or from time to time in part, at a redemption price equal to the sum of (1) the principal amount of the notes (or p ortion of such notes) being redeemed plus accrued and unpaid interest thereon up to the redemption date and (2) any “make-whole” amount due under the terms of the notes in connection with early redemptions. Redemptions and repurchases of debt, if any, wi ll depend on prevailing market conditions, our liquidity requirements, contractual restrictions and other factors. At March 31, 2018 , the annual principal payments due on these debt obligations were as follows (in thousands): Senior Secured Unsecured Notes (1,2) Debt (1,3) Totals 2018 $ - $ 350,257 $ 350,257 2019 600,000 483,773 1,083,773 2020 (4) 690,220 138,069 828,289 2021 (5,6) 1,143,934 228,870 1,372,804 2022 600,000 224,905 824,905 Thereafter (7,8) 4,972,835 1,072,521 6,045,356 Totals $ 8,006,989 $ 2,498,395 $ 10,505,384 (1) Amounts represent principal amounts due and do not include unamortized premiums/discounts, debt issuance costs, or other fair value adjustments as reflected on the balance sheet. (2) Annual interest rates range from 2.4% to 6.5%. (3) Annual interest rates range from 1.69% to 7.93%. Carrying value of the properties securing the debt totaled $5,272,358,000 at March 31, 2018. (4) In November 2015, one of our wholly-owned subsidiaries issued and we guaranteed $300,000,000 of Canadian-denominated 3.35% senior unsecured notes due 2020 (approximately $232,720,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018). (5) On May 13, 2016, we refinanced the funding on a $250,000,000 Canadian-denominated unsecured term credit facility (approximately $193,934,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018). The loan matures on May 13, 2021 and bears interest at the Canadian Dealer Offered Rate plus 95 basis points (2.55% at March 31, 2018). (6) On May 13, 2016, we refinanced the funding on a $500,000,000 unsecured term credit facility. The loan matures on May 13, 2021 and bears interest at LIBOR plus 95 basis points (2.7% at March 31, 2018). (7) On November 20, 2013, we completed the sale of £ 550,000,000 (approximately $771,485,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.8% senior unsecured notes due 2028. (8) On November 25, 2014, we completed the sale of £ 500,000,000 (approximately $701,350,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.5% senior unsecured notes due 2034. The following is a summary of our senior unsecured notes principal activity during the periods presented (dollars in thousands) : Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Amount Interest Rate Amount Interest Rate Beginning balance $ 8,417,447 4.306% $ 8,260,038 4.245% Debt extinguished (450,000) 2.250% - 0.000% Foreign currency 39,542 5.216% 24,229 4.391% Ending balance $ 8,006,989 4.451% $ 8,284,267 4.262% The following is a summary of our secured debt principal activity for the periods presented (dollars in thousands): Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Amount Interest Rate Amount Interest Rate Beginning balance $ 2,618,408 3.761% $ 3,465,066 4.094% Debt issued 20,326 3.774% 12,536 2.340% Debt assumed 85,192 4.395% - 0.000% Debt extinguished (183,408) 5.809% (806,189) 5.580% Foreign currency (27,876) 3.326% 10,313 3.262% Principal payments (14,247) 3.865% (16,249) 4.469% Ending balance $ 2,498,395 3.696% $ 2,665,477 3.744% Our debt agreements contain various covenants, restrictions and events of default. Certain agreements require us to maintain certain financial ratios and minimum net worth and impose certain limits on our ability to incur indebtedness, create liens and make investments or acquisitions. As of March 31, 2018 , we were in compliance with all of the covenants under our debt agreements.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Summary of Derivative Instruments [Abstract]
Derivative Instruments	11 . Derivative Instruments We are exposed to various market risks, including the potential loss arising from adverse changes in interest rates. We may elect to use financial derivative instruments to hedge interest rate exposure. These decisions are principally based on our policy to manage the general trend in interest rates at the applicable dates and our perception of the future volatility of interest rates. In addition, non-U.S. investments expose us to the potential losses associat ed with adverse changes in foreign currency to U.S. Dollar exchange rates. We may elect to manage this risk through the use of forward contracts and issuing debt in foreign currencies. Interest Rate Swap Contracts and Foreign Currency Forward Contrac ts Designated as Cash Flow Hedges For instruments that are designated and qualify as a cash flow hedge, the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive income (“OCI”), and reclassified into earnings in the same period or periods, during which the hedged transaction affects earnings. Gains and losses on the derivative representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in earnings. Foreign Currency Hedges For instruments that are designated and qualify as net investment hedges, the variability in the foreign currency to U.S. Dollar of the instrument is recorded as a cumulative translation adjustment component o f OCI. During the three months ended March 31, 2018 and 2017 , we settled certain net investment hedges necessitating cash payments of $8,055,000 and generating cash proceeds of $ 8,218 ,000, respectively. The balance of the cumulative translation adju stment will be reclassified to earnings when the hedged investment is sold or substantially liquidated. The following presents the notional amount of derivatives and other financial instruments as of the dates indicated (in thousands): March 31, 2018 December 31, 2017 Derivatives designated as net investment hedges: Denominated in Canadian Dollars $ 575,000 $ 575,000 Denominated in Pounds Sterling £ 550,000 £ 550,000 Financial instruments designated as net investment hedges: Denominated in Canadian Dollars $ 250,000 $ 250,000 Denominated in Pounds Sterling £ 1,050,000 £ 1,050,000 Derivatives designated as cash flow hedges: Denominated in Canadian Dollars $ 18,000 $ 36,000 Derivative instruments not designated: Denominated in Canadian Dollars $ 408,007 $ 408,007 Denominated in Pounds Sterling £ - £ 80,000 The following presents the impact of derivative instruments on the Consolidated S tatement s of C omprehensive I ncome for the periods presented (in thousands) : Three Months Ended March 31, Location 2018 2017 Gain (loss) on forward exchange contracts recognized in income Interest expense $ 1,195 $ 2,457 Gain (loss) on foreign exchange contracts and term loans designated as net investment hedge recognized in OCI OCI $ (62,698) $ (44,341)

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies	12 . Commitments and Contingencies At March 31, 2018 , we had 14 outstanding letter of credit obligations totaling $158,969,000 and expiring between 2018 and 2024 . At March 31, 2018 , we had outstanding construction in progress of $ 180,984,000 and were committed to providing additional funds of approximately $ 392,710,000 to complete construction. At March 31, 2018 , we had contingent purchase obligations totaling $ 10,350,000 . These contingent purchase obligations relate to unfunded capital improvement obligation s and contingent obligations on acquisitions. Rents due from the tenant are increased to reflect the additio nal investment in the property. We evaluate our leases for operating versus capital lease treatment in accordance with ASC Topic 840 “Leases.” A lease is classified as a capital lease if it provides for transfer of ownership of the leased asset at the end of the lease term, contains a bargain purchase option, has a lease term greater than 75% of the economic life of the leased asset, or if the n et present value of the future minimum lease payments are in excess of 90% of the fair value of the leased asset. Certain leases contain bargain purchase options and have been classified as capital leases. At March 31, 2018 , we had operating lease obligations o f $ 1,121,736,000 relating to certain ground leases and company office space and capital lease obligations of $ 87,922,000 relating primarily to certain investment properties. Regarding ground leases, we have sublease agreements with certain of our operators that require the operators to reimburse us for our monthly operating lease obligations. At March 31, 2018 , aggregate future minimum rentals to be received under these noncancelable subleases totaled $ 76,388,000 .

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity [Abstract]
Stockholders' Equity	13 . Stockholders’ Equity The following is a summary of our stockholders’ equity capital accounts as of the dates indicated: March 31, 2018 December 31, 2017 Preferred Stock: Authorized shares 50,000,000 50,000,000 Issued shares 14,375,000 14,375,000 Outstanding shares 14,369,965 14,370,060 Common Stock, $1.00 par value: Authorized shares 700,000,000 700,000,000 Issued shares 373,161,327 372,852,311 Outstanding shares 371,970,655 371,731,551 Preferred Stock. The following is a summary of our preferred stock activity during the periods indicated : Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Shares Dividend Rate Shares Dividend Rate Beginning balance 14,370,060 6.500% 25,875,000 6.500% Shares redeemed - 0.000% (11,500,000) 6.500% Shares converted (95) 6.500% - 0.000% Ending balance 14,369,965 6.500% 14,375,000 6.500% During the three months ended March 31, 2017 , we recognized a charge of $9,769,000 in connection with the redemption of the Series J preferred stock. Common Stock. The following is a summary of our common stock issuances during the three months ended March 31, 2018 and 2017 (dollars in thousands, except average price amounts): Shares Issued Average Price Gross Proceeds Net Proceeds 2017 Dividend reinvestment plan issuances 1,284,719 $ 68.33 $ 87,985 $ 87,784 2017 Option exercises 156,675 52.71 8,258 8,258 2017 Equity shelf program issuances 338,486 69.75 23,776 23,609 2017 Stock incentive plans, net of forfeitures 181,600 - - 2017 Totals 1,961,480 $ 120,019 $ 119,651 2018 Dividend reinvestment plan issuances 129,975 $ 55.51 $ 7,214 $ 7,214 2018 Preferred stock conversions 83 - - 2018 Stock incentive plans, net of forfeitures 109,046 - - 2018 Totals 239,104 $ 7,214 $ 7,214 Dividends . The increase in dividends is primarily attributable to increases in our common shares outstanding as described above . The following is a summary of our dividend payments (in thousands, except per share amounts): Three Months Ended March 31, 2018 March 31, 2017 Per Share Amount Per Share Amount Common Stock $ 0.8700 $ 323,726 $ 0.8700 $ 315,415 Series I Preferred Stock 0.8125 11,676 0.8125 11,680 Series J Preferred Stock - - 0.2347 2,699 Totals $ 335,402 $ 329,794 Accumulated Other Comprehensive Income . The following is a summary of accumulated other comprehensive income (loss) for the periods presented (in thousands): Unrecognized gains (losses) related to: Foreign Currency Translation Available for Sale Securities Actuarial Losses Cash Flow Hedges Total Balance at December 31, 2017 $ (110,581) $ - $ (884) $ - $ (111,465) Other comprehensive income before reclassification adjustments 20,212 - - - 20,212 Net current-period other comprehensive income 20,212 - - - 20,212 Balance at March 31, 2018 $ (90,369) $ - $ (884) $ - $ (91,253) Balance at December 31, 2016 $ (173,496) $ 5,120 $ (1,153) $ (2) $ (169,531) Other comprehensive income before reclassification adjustments 2,900 (10,569) - - (7,669) Net current-period other comprehensive income 2,900 (10,569) - - (7,669) Balance at March 31, 2017 $ (170,596) $ (5,449) $ (1,153) $ (2) $ (177,200)

Stock Incentive Plans

Stock Incentive Plans	3 Months Ended
	Mar. 31, 2018
Stock Incentive Plans [Abstract]
Stock Incentive Plans	14 . Stock Incentive Plans Our 2016 Long-Term Incentive Plan (“2016 Plan”) authorizes up to 10,000,000 shares of common stock to be issued at the discretion of the Compensation Committee of the Board of Directors. Our non-employee directors, officers and key employees are eligible to participate in the 2016 Plan. The 2016 Plan allows for the issuance of, among other things, stock options, sto ck appreciation rights, restricted stock, deferred stock units and dividend equivalent rights. Vesting periods for options, deferred stock units and restricted shares generally range from three to five years. Optio ns expire ten years from the date of grant. Stock-based compensation expense totaled $11,557 ,000 and $4,906 ,000 for the three months ende d March 31, 2018 and 2017 , respectively .

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	15 . Earnings Per Share The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data): Three Months Ended March 31, 2018 2017 Numerator for basic and diluted earnings per share - net income (loss) attributable to common stockholders $ 437,671 $ 312,639 Denominator for basic earnings per share - weighted average shares 371,426 362,534 Effect of dilutive securities: Employee stock options 15 70 Non-vested restricted shares 720 397 Redeemable shares 1,096 1,651 Dilutive potential common shares 1,831 2,118 Denominator for diluted earnings per share - adjusted weighted average shares 373,257 364,652 Basic earnings per share $ 1.18 $ 0.86 Diluted earnings per share $ 1.17 $ 0.86 The Series I Cumulative Convertible Perpetual Preferred Stock was not included in the calculations as the effect of conversions into common stock was anti-dilutive.

Disclosure about Fair Value of

Disclosure about Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2018
Disclosure About Fair Value of Financial Instruments [Abstract]
Disclosure about Fair Value of Financial Instruments	16 . Disclosure about Fair Value of Financial Instruments U.S. GAAP provides authoritative guidance for measuring and disclosing fair value measurements of assets and liabilities. The guidance defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The guidance also establi shes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Please see Note 2 to the financial statements included in our Annual Report on Form 10-K f or the year ended December 31, 2017 for additional information. The guidance describes three levels of inputs that may be used to measure fair value: Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets o r liabilities. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The following methods and assumptions were used to estimate the fair value of each class of financial instruments for which it is practicable to estimate that value. Mortgage Loans and Other Real Estate Loans Receivable — The fair value of mortgage loans and other real estate loans receivable is generally estimated by using Level 2 and Level 3 inputs such as discounting the estimated future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities. Cash and Cash Equivalents and Restricted Cash — The carrying amount approximates fair value. Available-for-sale Equity Investments — Available-for-sale equity investments are recorded at their fair value based on Level 1 publicly available trading prices. Borrowings Under Primary Unsecured Credit Facility — The c arrying amount of the primary unsecured credit facility approximates fair value because the borrowings are interest rate adjustable. Senior Unsecured Notes — The fair value of the senior unsecured notes payable was estimated based on Level 1 publicly avai lable trading prices. The carrying amount of the variable rate senior unsecured notes approximates fair value because they are interest rate adjustable. Secured Debt — The fair value of fixed rate secured debt is estimated using Level 2 inputs by discount ing the estimated future cash flows using the current rates at which similar loans would be made with similar credit ratings and for the same remaining maturities. The carrying amount of variable rate secured debt approximates fair value because the borro wings are interest rate adjustable. Foreign Currency Forward Contracts — Foreign currency forward contracts are recorded in other assets or other liabilities on the balance sheet at fair market value. Fair market value is determined using Level 2 inputs by estimating the future value of the currency pair based on existing exchange rates, comprised of current spot and traded forward points, and calculating a present value of the net amount using a discount factor based on observable traded interest rates. Redeemable OP Unitholder Interests — Our redeemable unitholder interests are recorded on the balance sheet at fair value using Level 2 inputs. The fair value is measured using the closing price of our common stock, as units may be redeemed at the electio n of the holder for cash or, at our option, one share of our common stock per unit, subject to adjustment in certain circumstances. The carrying amounts and estimated fair values of our financial instruments are as follows (in thousands): March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Mortgage loans receivable $ 264,948 $ 271,887 $ 306,120 $ 332,508 Other real estate loans receivable 102,874 108,850 121,379 125,480 Available-for-sale equity investments 14,443 14,443 7,269 7,269 Cash and cash equivalents 202,824 202,824 243,777 243,777 Restricted cash 61,295 61,295 65,526 65,526 Foreign currency forward contracts 28,713 28,713 15,604 15,604 Financial liabilities: Borrowings under unsecured credit facilities $ 865,000 $ 865,000 $ 719,000 $ 719,000 Senior unsecured notes 7,924,340 8,582,136 8,331,722 9,168,432 Secured debt 2,488,652 2,465,270 2,608,976 2,641,997 Foreign currency forward contracts 58,190 58,190 38,654 38,654 Redeemable OP unitholder interests $ 97,476 $ 97,476 $ 97,476 $ 97,476 Items Measured at Fair Value on a Recurring Basis The market approach is utilized to measure fair value for our financial assets and liabilities reported at fair value on a recurring basis. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The following summarizes items measured at fair value on a recurring basis (in thousands): Fair Value Measurements as of March 31, 2018 Total Level 1 Level 2 Level 3 Available-for-sale equity investments $ 14,443 $ 14,443 $ - $ - Foreign currency forward contracts, net asset (liability) (1) (29,477) - (29,477) - Redeemable OP unitholder interests 97,476 - 97,476 - Totals $ 82,442 $ 14,443 $ 67,999 $ - (1) Please see Note 11 for additional information. Items Measured at Fair Value on a Nonrecurring Basis In addition to items that are measured at fair value on a recurring basis, we also have assets and liabilities in our balance sheet that are measured at fair value on a nonrecurring basis. As these assets and liabilities are not measured at fair value on a recurring basis, they are not included in the tables above. Assets, liabilities and noncontrolling interests that are measured at fair value on a nonrecurring basis include those acquired/assumed. Asset impairments (if applicable, see Note 5 for impairments of real property and Note 6 for impairments of loans receivable) are also measured at fair value on a nonrecurring basis. We have determined that the fair value measurements included in each of t hese assets and liabilities rely primarily on company-specific inputs and our assumptions about the use of the assets and settlement of liabilities, as observable inputs are not available. As such, we have determined that each of these fair value measureme nts generally resides within Level 3 of the fair value hierarchy. We estimate the fair value of real estate and related intangibles using the income approach and unobservable data such as net operating income and estimated capitalization and discount rates . We also consider local and national industry market data including comparable sales, and commonly engage an external real estate appraiser to assist us in our estimation of fair value. We estimate the fair value of assets held for sale based on current sales price expectations or, in the absence of such price expectations, Level 3 inputs described above. We estimate the fair value of loans receivable using projected payoff valuations based on the expected future cash flows and/or the estimated fair value of collateral, net of sales costs, if the repayment of the loan is expected to be provided solely by the collateral. We estimate the fair value of secured debt assumed in business combinations and asset acquisitions using current interest rates at which similar borro wings could be obtained on the transaction date.

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	17 . Segment Reporting We invest in seniors housing and health care real estate. We evaluate our business and make resource allocations on our three operating segments: triple-net, seniors housing ope rating and outpatient medical. Our triple-net properties include long-term/post-acute care facilities, assisted living facilities, independent living/continuing care retirement communities, care homes (United Kingdom), independent support living facilities (Canada), care homes with nursing (United Kingdom) and combinations thereof. Under the triple-net segment, we invest in seniors housing and health care real estate through acquisition and financing of primarily single tenant properties. Properties acquired are primarily leased under triple -net leases and we are not involved in the management of the property. Our seniors housing operating properties include the seniors housing communities referenced above that are owned and/or operated through RIDEA structures (see Note 18). Our outpatient m edical properties are typically leased to multiple tenants and generally require a certain level of property management. We evaluate performance based upon consolidated net operating income (“NOI”) of each segment. We define NOI as total revenues, inc luding tenant reimbursements, less property operating expenses. We believe NOI provides investors relevant and useful information as it measures the operating performance of our properties at the property level on an unleveraged basis. We use NOI to make d ecisions about resource allocations and to assess the property level performance of our properties. Non-segment revenue consists mainly of interest income on certain non-real estate investments and other income. Non-segment assets consist of corp orate assets including cash, deferred loan expenses and corporate offices and equipment among others. Non-property specific revenues and expenses are not allocated to individual segments in determining NOI. The accounting policies of the segments are the s ame as those described in the summary of significant accounting policies (see Note 2 to the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017 ). The results of operations for all acquisitions described i n Note 3 are included in our consolidated results of operations from the acquisition dates and are components of the appropriate segments. There are no intersegment sales or transfers. Summary information for the reportable segments (which excludes unconsolidated entities) is as follows (in thousands): Three Months Ended March 31, 2018: Triple-net Seniors Housing Operating Outpatient Medical Non-segment / Corporate Total Rental income $ 206,831 $ - $ 136,538 $ - $ 343,369 Resident fees and services - 735,934 - - 735,934 Interest income 14,551 85 12 - 14,648 Other income 1,377 1,148 121 368 3,014 Total revenues 222,759 737,167 136,671 368 1,096,965 Property operating expenses 21 511,941 44,503 - 556,465 Consolidated net operating income 222,738 225,226 92,168 368 540,500 Interest expense 3,442 16,935 1,676 100,722 122,775 Loss (gain) on derivatives and financial instruments, net (7,173) - - - (7,173) Depreciation and amortization 56,032 125,769 46,400 - 228,201 General and administrative - - - 33,705 33,705 Loss (gain) on extinguishment of debt, net (32) (189) 11,928 - 11,707 Impairment of assets 25,884 2,301 - - 28,185 Other expenses 1,120 (188) 598 2,182 3,712 Income (loss) from continuing operations before income taxes and income from unconsolidated entities 143,465 80,598 31,566 (136,241) 119,388 Income tax (expense) benefit (1,136) 162 (428) (186) (1,588) Income (loss) from unconsolidated entities 5,821 (9,480) 1,230 - (2,429) Income (loss) from continuing operations 148,150 71,280 32,368 (136,427) 115,371 Gain (loss) on real estate dispositions, net 123,397 5 214,782 - 338,184 Net income (loss) $ 271,547 $ 71,285 $ 247,150 $ (136,427) $ 453,555 Total assets $ 8,937,964 $ 13,769,265 $ 4,911,566 $ 127,864 $ 27,746,659 Three Months Ended March 31, 2017: Triple-net Seniors Housing Operating Outpatient Medical Non-segment / Corporate Total Rental income $ 227,290 $ - $ 139,851 $ - $ 367,141 Resident fees and services - 670,337 - - 670,337 Interest income 20,679 69 - - 20,748 Other income 1,766 1,461 612 233 4,072 Total revenues 249,735 671,867 140,463 233 1,062,298 Property operating expenses - 462,425 47,744 - 510,169 Consolidated net operating income 249,735 209,442 92,719 233 552,129 Interest expense 5,511 15,816 2,291 94,979 118,597 Loss (gain) on derivatives and financial instruments, net 1,224 - - - 1,224 Depreciation and amortization 59,608 119,737 48,931 - 228,276 General and administrative - - - 31,101 31,101 Loss (gain) on extinguishment of debt, net 29,084 890 1,382 - 31,356 Impairment of assets - 5,406 5,625 - 11,031 Other expenses 5,010 1,778 360 4,527 11,675 Income (loss) from continuing operations before income taxes and income from unconsolidated entities 149,298 65,815 34,130 (130,374) 118,869 Income tax (expense) benefit (800) (1,087) (335) (23) (2,245) Income (loss) from unconsolidated entities 5,638 (29,191) (1) 447 - (23,106) Income (loss) from continuing operations 154,136 35,537 34,242 (130,397) 93,518 Gain (loss) on real estate dispositions, net 231,081 13,011 - - 244,092 Net income (loss) $ 385,217 $ 48,548 $ 34,242 $ (130,397) $ 337,610 (1) Primarily due to the recognition of goodwill and intangible asset impairments on unconsolidated joint ventures, as well as non-recurring income tax expense. Our portfolio of properties and other investments are located in the United States, the United Kingdom and Canada. Revenues and assets are attributed to the country in which the property is physically located . The following is a summary of geographic information for the periods presented (dollars in thousands): Three Months Ended March 31, 2018 March 31, 2017 Revenues: Amount % Amount % United States $ 863,789 78.8% $ 858,668 80.9% United Kingdom 116,525 10.6% 93,843 8.8% Canada 116,651 10.6% 109,787 10.3% Total $ 1,096,965 100.0% $ 1,062,298 100.0% As of March 31, 2018 December 31, 2017 Assets: Amount % Amount % United States $ 21,847,420 78.7% $ 22,274,443 79.7% United Kingdom 3,397,904 12.3% 3,239,039 11.6% Canada 2,501,335 9.0% 2,430,963 8.7% Total $ 27,746,659 100.0% $ 27,944,445 100.0%

Income Taxes and Distributions

Income Taxes and Distributions	3 Months Ended
	Mar. 31, 2018
Income Taxes And Distributions [Abstract]
Income Taxes And Distributions	18 . Income Taxes and Distributions We elected to be taxed as a REIT commencing with our first taxable year. To qualify as a REIT for federal income tax purposes, at least 90% of taxable income (excluding 100% of net capital gains) must be distributed to stockholders. REITs that do not distribute a certain amount of current year taxable income in the current year are also subject to a 4% federal excise tax. The main differences between undistributed net income for federal income tax purposes and financial statement purposes are the recognition of straight-line rent for reporting purposes, basis differences in acquisitions, recording of impairments, differing useful lives and depreciation and amortization methods for real property and the prov ision for loan losses for reporting purposes versus bad debt expense for tax purposes. Under the provisions of the REIT Investment Diversification and Empowerment Act of 2007 (“RIDEA”), for taxable years beginning after July 30, 2008, a REIT may leas e “qualified health care properties” on an arm’s-length basis to a taxable REIT subsidiary (“TRS”) if the property is operated on behalf of such TRS by a person who qualifies as an “eligible independent contractor.” Generally, the rent received from the TR S will meet the related party rent exception and will be treated as “rents from real property.” A “qualified health care property” includes real property and any personal property that is, or is necessary or incidental to the use of, a hospital, nursing f acility, assisted living facility, congregate care facility, qualified continuing care facility, or other licensed facility which extends medical or nursing or ancillary services to patients. We have entered into various joint ventures that were structured under RIDEA. Resident level rents and related operating expenses for these facilities are reported in the unaudited consolidated financial statements and are subject to federal and state income taxes as the operations of such facilities are included in TR S entities. Certain net operating loss carryforwards could be utilized to offset taxable income in future years. Income taxes reflected in the financial statements primarily represents U.S. federal and state and local income taxes as well as non-U.S. income based or withholding taxes on certain investments located in jurisdictions outside the U.S. The provision for income taxes for the three months ended March 31, 2018 and 2017 , was primarily due to operating income or losses, offset by certain di screte items at our TRS entities. In 2014, we established certain wholly-owned direct and indirect subsidiaries in Luxembourg and Jersey and transferred interests in certain foreign investments into this holding company structure. The structure includes a property holding company that is tax resident in the United Kingdom. No material adverse current tax consequences in Luxembourg, Jersey or the United Kingdom resulted from the creation of this holding company structure and most of the subsidiary entities in the structure are treated as disregarded entities of the company for U.S. federal income tax purposes. The company reflects current and deferred tax liabilities for any such withholding taxes incurred as a result of this holding company structure in i ts consolidated financial statements. Generally, given current statutes of limitations, we are subject to audit by the Internal Revenue Service (“IRS”) for the year ended December 31, 201 4 and subsequent years and by state taxing authorities for the year e nded December 31, 201 3 and subsequent years. The company and its subsidiaries are also subject to audit by the Canada Revenue Agency and provincial authorities generally for periods subsequent to our initial investments in Canada in May 2012, by HM Revenu e & Customs for periods subsequent to our initial investments in the United Kingdom in August 2012 and by Luxembourg taxing authorities generally for periods subsequent to our establishment of certain Luxembourg-based subsidiaries during 2014.

Variable Interest Entity Disclo

Variable Interest Entity Disclosure	3 Months Ended
	Mar. 31, 2018
Variable Interest Entity Disclosure [Abstract]
Variable Interest Entity Disclosure [Text Block]	19 . Variable Interest Entities We have entered into joint ventures to own certain seniors housing and outpatient medical assets which are deemed to be variable interest entities (“VIE”). We have concluded that we are the primary beneficiary of these VIEs based on a combination of operational control of the joint venture and the rights to receive residual returns or the obligation to absorb losses arising from the joint ventures. Except for capital contributions associated with the initial joint venture formations , the joint ventures have been a nd are expected to be funded from the ongoing operations of the underlying properties. Accordingly, such joint ventures have been consolidated, and t he table below summarizes the balance sheets of consolidated VIEs in the aggregate (in thousands): March 31, 2018 December 31, 2017 Assets Net real property owned $ 993,156 $ 1,002,137 Cash and cash equivalents 16,871 12,308 Receivables and other assets 17,198 16,330 Total assets (1) $ 1,027,225 $ 1,030,775 Liabilities and equity Secured debt $ 469,757 $ 471,103 Accrued expenses and other liabilities 16,501 14,832 Redeemable noncontrolling interests 171,035 171,898 Total equity 369,932 372,942 Total liabilities and equity $ 1,027,225 $ 1,030,775 (1) Note that assets of the consolidated VIEs can only be used to settle obligations relating to such VIEs. Liabilities of the consolidated VIEs represent claims against the specific assets of the VIEs.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	20 . S ubsequent Events Senior Notes Subsequent to March 31, 2018 , we completed the issuance of $550,000,000 of 4.25% senior unsecured notes due 2028 for net proceeds of approximately $545,199,000. Strategic Joint Venture Commitment Subsequent to March 31, 2018 , we entered into a definitive agreement (the “Merger Agreement”) to acquire all of the outstanding shares of Quality Care Properties, Inc. (“QCP”) in an all cash deal for $20.75 per share (the “QCP Acquisition”). Concurrent with this agreement, we formed an 80/20 joint venture with ProMedica to own the real estate of QCP’s principal tenants, HCR ManorCare and Arden Courts , the operations of which will be acquired by ProMedica. Our joint venture investment is estimated to be $2.2 billion and upon completion of the transactions, ProMedica will enter into a new lease agreement with the following key terms: (i) 15-year absolute triple-net master lease with three five-year renewal options; (ii) 8% initial cash rental yield with a year one escalator of 1.375% and 2.75% annual escalator thereafter; and (iii) full corporate guarantee of ProMedica . In connection with the QCP Acquisition, we have entered into a debt commitment letter with Barclays Bank PLC (“Barclays”), pursuant to which Barclays has commit ted to provide a $1.0 billion senior unsecured bridge credit facility. The bridge facility may be used to pay a portion of the QCP Acquisition cash consideration and other related expenses. The Merger Agreement contemplates that we may issue notes or ter m loans in lieu of a portion or all of the drawings under this bridge facility.

Accounting Policies and Relat27

Accounting Policies and Related Matters (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies and Related Matters (Policies) [Abstract]
Basis of Presentation	2 . Accounting Policies and Related Matters Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments ( such as normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2018 are not necessarily an indication of the results that may be expect ed for the year ending December 31, 2018 . For further information, refer to the financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017 .
New Accounting Standards	New Accounting Standards We adopted the followin g accounting standards, each of which did not have a material impact on our consolidated financial statements: In 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts wi th Customers (ASC 606),” which is a comprehensive new revenue recognition model that requires revenue to be recognized in a manner to depict the transfer of goods or services to a customer at an amount that reflects the consideration expected to be receive d in exchange for those goods or services. We adopted ASC 606 on January 1, 2018 using the modified retrospective method of adoption . This guidance did not have a significant impact on our consolidated financial statements. We have evaluated our various revenue streams to identify whether they would be subject to the provisions of ASC 606 and any differences in timing, measurement or presentation of revenue recognition. A significant source of our revenue is generated through leasing arrangements, which are specifically excluded from ASC 606. Management contracts are present in our seniors ho using operating and outpatient medical segments and represent agreements to provide asset and property management, leasing, marketing and other services. Under ASC 606, the pattern and timing of recognition of income from these contracts is consistent wit h the prior accounting model. In 2017, the FASB issued ASU No. 2017-05, “Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sale s of Nonfinancial Assets.” The standard clarifies that a financial asset is within the scope of Subtopic 610-20 if it meets the definition of an in substance nonfinancial asset. The standard also defines the term “ in substance nonfinancial asset” and clarifies t hat an entity should identify each distinct nonfinancial asset or in substance nonfinancial asset promised to a counterparty and derecognize each asset when a counterparty obtains control over it. We adopted Subtopic 610-20 using a modified retrospective approach on January 1, 2018. In 2016, the FASB issued ASU No. 2016-01, “Financial Instruments – Overall: Recognition and Measurement of Financial Assets and Financial Liabilities,” which requires entities to measure their investments at fair value and reco gnize any changes in fair value in net income unless the investments qualify for the new practicability exception. The practicability exception is available for equity investments that do not have readily determinable fair values. This standard requires u s to recognize gains and losses from changes in the fair value of our available-for-sale equity securities through the consolidated statement of comprehensive income rather than through accumulated other comprehensive income. During the three months ended March 31, 2018, we recognized a gain of $7,173,000 in loss (gain) on derivatives and financial instruments, net on the consolidated statement of comprehensive income. There was no adjustment to accumulated other comprehensive income upon adoption at Janua ry 1, 2018 as accumulated losses were recognized as other-than-temporary impairment during the year ended December 31, 2017. During the three months ended December 31, 2017, we adopted ASU No. 2016-18, “Restricted Cash,” and ASU No . 2016-15, “Classification of Certain Cash Receipts and Cash Payments.” ASU No. 2016-18 requires an entity to reconcile and explain the period over period change in total cash, cash equivalents and restricted cash within its consolidated statement of cash flows and ASU 2016-15 provides guidance clarifying how certain cash receipts and cash payments should be classified. We adopted these accounting standards retrospectively and, accordingly, certain line items in the consolidated statement of cash flows ha ve been reclassified to conform to the current presentation. The following table summarizes the change in cash flows as reported and as previously reported prior to the adoption of these standards for the three months ended March 31, 2017 (in thousa nds): As Previously As Reported Reported Cash disbursed for acquisitions $ (102,356) $ (102,356) Decrease (increase) in restricted cash - 145,065 Net cash provided from (used in) investing activities 920,174 1,065,239 Increase (decrease) in balance (1) (184,083) (39,018) Balance at beginning of period (1) 607,220 419,378 Balance at end of period (1) 423,137 380,360 (1) Amounts in As Reported column include cash and cash equivalents and restricted cash as required. Amounts in the As Previously Reported column reflect only cash and cash equivalents. The following ASUs have been issued but not yet adopted: In 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842),” which requires lessees to recognize assets and liabilities on their consolidated balance sheet related to the rights and obligations created by most leases, while continuing to recognize expenses on their consolidated statements of comprehensive income over the lease term. It will also require disclosures designed to give financial statement users information regarding amou nt, timing, and uncertainty of cash flows arising from leases. The FASB issued an Exposure Draft in January 2018 proposing to amend ASU 2016-02, which would provide lessors with a practical expedient, by class of underlying assets, to not separate non-lea se components from the related lease components and, instead, to account for those components as a single lease component, if certain criteria are met. ASU 2016-02 and the Exposure Draft are effective for us beginning January 1, 2019, with early adoption permitted. Entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the consolidated financial statements. We are currently evaluating the impact of this guidance on our consolidated financial statements from both the lessee and lessor perspective. We believe that adoption will likely have a material impact to our consolidated financial statements for the recognition of certain operating leases as ri ght-of-use assets and lease liabilities and related amortizations. We expect to utilize the practical expedients proposed in the Exposure Draft as part of our adoption of this guidance. In 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Los ses on Financial Instruments.” This standard requires a new forward-looking “expected loss” model to be used for receivables, held-to-maturity debt, loans, and other instruments. ASU 2016-13 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, and early adoption is permitted for fiscal years beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. In August 2017, th e FASB issued ASU 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities,” which expands and refines hedge accounting for both nonfinancial and financial risk components and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. It also includes certain targeted improvements to simplify the application of current guidance related to hedge accounting. The standard is effective for fiscal years, a nd interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. We expect to adopt this guidance during the three months ended June 30, 2018 and are currently evaluating the impact th e effects this standard will have on our consolidated financial statements .

Accounting Policies and Relat28

Accounting Policies and Related Matters (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies and Related Matters (Tables) [Abstract]
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy	As Previously As Reported Reported Cash disbursed for acquisitions $ (102,356) $ (102,356) Decrease (increase) in restricted cash - 145,065 Net cash provided from (used in) investing activities 920,174 1,065,239 Increase (decrease) in balance (1) (184,083) (39,018) Balance at beginning of period (1) 607,220 419,378 Balance at end of period (1) 423,137 380,360 (1) Amounts in As Reported column include cash and cash equivalents and restricted cash as required. Amounts in the As Previously Reported column reflect only cash and cash equivalents.

Real Property Acquisitions an29

Real Property Acquisitions and Development (Tables)	3 Months Ended
	Mar. 31, 2018
Real property acquisitions and development [Line Items]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities	Triple-n et Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 1,691 $ 4,017 Buildings and improvements 235 37,241 Total assets acquired 1,926 41,258 Accrued expenses and other liabilities (6) - Total liabilities assumed (6) - Cash disbursed for acquisitions (1) 1,920 41,258 Construction in progress additions 15,850 46,754 Less: Capitalized interest (847) (2,028) Foreign currency translation - (164) Cash disbursed for construction in progress 15,003 44,562 Capital improvements to existing properties 2,351 10,495 Total cash invested in real property, net of cash acquired $ 19,274 $ 96,315 (1) Primarily reprsents land acquired on an existing property during the three months ended March 31, 2018. Seniors Housing Operating Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 35,193 $ 4,304 Building and improvements 372,562 44,075 Acquired lease intangibles 48,805 1,741 Receivables and other assets 265 74 Total assets acquired (1) 456,825 50,194 Secured debt (89,973) - Accrued expenses and other liabilities (12,808) (2,755) Total liabilities assumed (102,781) (2,755) Noncontrolling interests (5,618) (647) Non-cash acquisition related activity (2) - (14,148) Cash disbursed for acquisitions 348,426 32,644 Construction in progress additions 10,562 8,062 Less: Capitalized interest (891) (1,707) Foreign currency translation (5,032) 691 Cash disbursed for construction in progress 4,639 7,046 Capital improvements to existing properties 31,325 24,254 Total cash invested in real property, net of cash acquired $ 384,390 $ 63,944 (1) Excludes $2,155,000 and $400,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018 and 2017, respectively. (2) Includes $6,349,000 related to the acquisition of assets previously financed as real estate loans receivable and $7,799,000 previously financed as an investment in an unconsolidated entity during the three months ended March 31, 2017. Outpatient Medical Activity Three Months Ended (In thousands) March 31, 2018 March 31, 2017 Land and land improvements $ 7,369 $ 2,895 Buildings and improvements 42,673 23,310 Acquired lease intangibles 5,852 3,496 Receivables and other assets 1 3 Total assets acquired (1) 55,895 29,704 Accrued expenses and other liabilities (632) (1,250) Total liabilities assumed (632) (1,250) Cash disbursed for acquisitions 55,263 28,454 Construction in progress additions 2,803 14,921 Less: Capitalized interest (598) (717) Accruals (2) 888 3,522 Cash disbursed for construction in progress 3,093 17,726 Capital improvements to existing properties 12,871 7,366 Total cash invested in real property $ 71,227 $ 53,546 (1) Excludes $1,950,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018. (2) Represents non-cash accruals for amounts to be paid in future periods for properties that converted, off-set by amounts paid in the current period. Construction Activity Three Months Ended March 31, 2018 March 31, 2017 Development projects: Triple-net $ 49,759 $ 157,460 Seniors housing operating 36,218 3,634 Outpatient medical - 25,910 Total development projects 85,977 187,004 Total construction in progress conversions $ 85,977 $ 187,004

Real Estate Intangibles (Tables

Real Estate Intangibles (Tables)	3 Months Ended
	Mar. 31, 2018
Real Estate Intangibles (Tables) [Abstract]
Summary of real estate intangibles excluding those classified as held for sale	March 31, 2018 December 31, 2017 Assets: In place lease intangibles $ 1,395,920 $ 1,352,139 Above market tenant leases 58,402 58,443 Below market ground leases 59,030 58,784 Lease commissions 35,269 33,105 Gross historical cost 1,548,621 1,502,471 Accumulated amortization (1,149,223) (1,125,437) Net book value $ 399,398 $ 377,034 Weighted-average amortization period in years 14.4 15.1 Liabilities: Below market tenant leases $ 71,706 $ 60,430 Above market ground leases 8,540 8,540 Gross historical cost 80,246 68,970 Accumulated amortization (40,400) (39,629) Net book value $ 39,846 $ 29,341 Weighted-average amortization period in years 16.0 20.1
Schedule of Real Estate Intangible Amortization	Three Months Ended March 31, 2018 2017 Rental income related to above/below market tenant leases, net $ (351) $ 304 Property operating expenses related to above/below market ground leases, net 367 (312) Depreciation and amortization related to in place lease intangibles and lease commissions (32,261) (39,302)
Schedule of the future estimated aggregate amortization of intangible assets and liabilities	Assets Liabilities 2018 $ 94,521 $ 4,470 2019 74,771 5,582 2020 47,871 5,085 2021 20,985 4,597 2022 17,770 4,132 Thereafter 143,480 15,980 Total $ 399,398 $ 39,846

Dispositions, Assets Held for31

Dispositions, Assets Held for Sale and Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2018
Dispositions, Assets Held for Sale and Discontinued Operations (Tables) [Abstract]
Summary of real property disposition activity	Three Months Ended March 31, 2018 March 31, 2017 Real estate dispositions: Triple-net $ 323,667 $ 808,204 Seniors housing operating 2,200 13,845 Outpatient medical 223,069 - Total dispositions 548,936 822,049 Gain (loss) on real estate dispositions, net 338,184 244,092 Net other assets/liabilities disposed 5,089 20,933 Proceeds from real estate dispositions $ 892,209 $ 1,087,074
Summary of disposed properties.	Three Months Ended March 31, 2018 2017 Revenues: Rental income $ 13,886 $ 43,787 Expenses: Interest expense 127 2,707 Property operating expenses 7,256 8,521 Provision for depreciation 1,741 9,813 Total expenses 9,124 21,041 Income (loss) from real estate dispositions, net $ 4,762 $ 22,746

Real Estate Loans Receivable (T

Real Estate Loans Receivable (Tables)	3 Months Ended
	Mar. 31, 2018
Real Estate Loans Receivable (Tables) [Abstract]
Summary of real estate loan activity	Three Months Ended March 31, 2018 March 31, 2017 Senior Senior Housing Outpatient Housing Outpatient Triple-net Operating Medical Totals Triple-net Operating Medical Totals Advances on real estate loans receivable: Investments in new loans $ 1,172 $ 11,806 $ 2,458 $ 15,436 $ 7,828 $ - $ - $ 7,828 Draws on existing loans 12,111 - - 12,111 17,547 - - 17,547 Net cash advances on real estate loans 13,283 11,806 2,458 27,547 25,375 - - 25,375 Receipts on real estate loans receivable: Loan payoffs 58,557 - - 58,557 14,474 - 60,500 74,974 Principal payments on loans 32,174 - - 32,174 667 - - 667 Sub-total 90,731 - - 90,731 15,141 - 60,500 75,641 Less: Non-cash activity (1) - - - - (6,349) - (60,500) (66,849) Net cash receipts on real estate loans 90,731 - - 90,731 8,792 - - 8,792 Net cash advances (receipts) on real estate loans $ (77,448) $ 11,806 $ 2,458 $ (63,184) $ 16,583 $ - $ - $ 16,583 (1) Triple-net represents acquisitions of assets previously financed as real estate loans. Please see Note 3 for additional information. Outpatient medical represents a deed in lieu of foreclosure on a previously financed first mortgage property. Three Months Ended March 31, 2018 March 31, 2017 Balance of impaired loans at end of period $ 214,896 $ 317,049 Allowance for loan losses 68,372 6,196 Balance of impaired loans not reserved $ 146,524 $ 310,853 Average impaired loans for the period $ 265,973 $ 340,920 Interest recognized on impaired loans (1) 5,327 8,243 (1) Represents cash interest recognized in the period since loans were identified as impaired.

Investments in Unconsolidated33

Investments in Unconsolidated Entities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments In Unconsolidated Entities [Abstract]
Summary Of Investments In Unconsolidated Entities [Text Block]	Percentage Ownership (1) March 31, 2018 December 31, 2017 Triple-net 10% to 49% $ 22,440 $ 22,856 Seniors housing operating 10% to 50% 338,154 352,430 Outpatient medical 43% 79,830 70,299 Total $ 440,424 $ 445,585 (1) Excludes in-substance real estate investments.

Credit Concentration (Tables)

Credit Concentration (Tables)	3 Months Ended
	Mar. 31, 2018
Customer Concentration (Tables) [Abstract]
Summary of credit concentration	Number of Total Percent of Concentration by relationship: (1) Properties NOI NOI (2) Sunrise Senior Living (3) 160 $ 79,838 15% Revera (3) 98 39,525 7% Brookdale Senior Living 137 36,865 7% Genesis HealthCare 86 34,773 6% Benchmark Senior Living 48 23,948 4% Remaining portfolio 728 325,551 61% Totals 1,257 $ 540,500 100% (1) Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments. (2) NOI with our top five relationships comprised 41% of total NOI for the year ended December 31, 2017. (3) Revera owns a controlling interest in Sunrise Senior Living.

Borrowings Under Credit Facil35

Borrowings Under Credit Facilities and Related Items (Tables)	3 Months Ended
	Mar. 31, 2018
Borrowings Under Credit Facilities and Related Items (Tables) [Abstract]
Aggregate borrowings under the unsecured line of credit arrangements	Three Months Ended March 31, 2018 2017 Balance outstanding at quarter end (1) $ 865,000 $ 522,000 Maximum amount outstanding at any month end $ 865,000 $ 1,010,000 Average amount outstanding (total of daily principal balances divided by days in period) $ 364,111 $ 796,356 Weighted average interest rate (actual interest expense divided by average borrowings outstanding) 2.72% 1.81% (1) As of March 31, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.

Senior Unsecured Notes and Se36

Senior Unsecured Notes and Secured Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Senior Unsecured Notes And Secured Debt (Tables) [Abstract]
Principal payments due on debt obligations	Senior Secured Unsecured Notes (1,2) Debt (1,3) Totals 2018 $ - $ 350,257 $ 350,257 2019 600,000 483,773 1,083,773 2020 (4) 690,220 138,069 828,289 2021 (5,6) 1,143,934 228,870 1,372,804 2022 600,000 224,905 824,905 Thereafter (7,8) 4,972,835 1,072,521 6,045,356 Totals $ 8,006,989 $ 2,498,395 $ 10,505,384 (1) Amounts represent principal amounts due and do not include unamortized premiums/discounts, debt issuance costs, or other fair value adjustments as reflected on the balance sheet. (2) Annual interest rates range from 2.4% to 6.5%. (3) Annual interest rates range from 1.69% to 7.93%. Carrying value of the properties securing the debt totaled $5,272,358,000 at March 31, 2018. (4) In November 2015, one of our wholly-owned subsidiaries issued and we guaranteed $300,000,000 of Canadian-denominated 3.35% senior unsecured notes due 2020 (approximately $232,720,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018). (5) On May 13, 2016, we refinanced the funding on a $250,000,000 Canadian-denominated unsecured term credit facility (approximately $193,934,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018). The loan matures on May 13, 2021 and bears interest at the Canadian Dealer Offered Rate plus 95 basis points (2.55% at March 31, 2018). (6) On May 13, 2016, we refinanced the funding on a $500,000,000 unsecured term credit facility. The loan matures on May 13, 2021 and bears interest at LIBOR plus 95 basis points (2.7% at March 31, 2018). (7) On November 20, 2013, we completed the sale of £ 550,000,000 (approximately $771,485,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.8% senior unsecured notes due 2028. (8) On November 25, 2014, we completed the sale of £ 500,000,000 (approximately $701,350,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.5% senior unsecured notes due 2034.
Summary of senior unsecured note activity	Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Amount Interest Rate Amount Interest Rate Beginning balance $ 8,417,447 4.306% $ 8,260,038 4.245% Debt extinguished (450,000) 2.250% - 0.000% Foreign currency 39,542 5.216% 24,229 4.391% Ending balance $ 8,006,989 4.451% $ 8,284,267 4.262%
Secured debt principal activity	Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Amount Interest Rate Amount Interest Rate Beginning balance $ 2,618,408 3.761% $ 3,465,066 4.094% Debt issued 20,326 3.774% 12,536 2.340% Debt assumed 85,192 4.395% - 0.000% Debt extinguished (183,408) 5.809% (806,189) 5.580% Foreign currency (27,876) 3.326% 10,313 3.262% Principal payments (14,247) 3.865% (16,249) 4.469% Ending balance $ 2,498,395 3.696% $ 2,665,477 3.744%

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments (Tables) [Abstract]
Impact of derivative instruments on the statement of operations and OCI	March 31, 2018 December 31, 2017 Derivatives designated as net investment hedges: Denominated in Canadian Dollars $ 575,000 $ 575,000 Denominated in Pounds Sterling £ 550,000 £ 550,000 Financial instruments designated as net investment hedges: Denominated in Canadian Dollars $ 250,000 $ 250,000 Denominated in Pounds Sterling £ 1,050,000 £ 1,050,000 Derivatives designated as cash flow hedges: Denominated in Canadian Dollars $ 18,000 $ 36,000 Derivative instruments not designated: Denominated in Canadian Dollars $ 408,007 $ 408,007 Denominated in Pounds Sterling £ - £ 80,000 Three Months Ended March 31, Location 2018 2017 Gain (loss) on forward exchange contracts recognized in income Interest expense $ 1,195 $ 2,457 Gain (loss) on foreign exchange contracts and term loans designated as net investment hedge recognized in OCI OCI $ (62,698) $ (44,341)

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity (Tables) [Abstract]
Summary of stockholder's equity capital accounts	March 31, 2018 December 31, 2017 Preferred Stock: Authorized shares 50,000,000 50,000,000 Issued shares 14,375,000 14,375,000 Outstanding shares 14,369,965 14,370,060 Common Stock, $1.00 par value: Authorized shares 700,000,000 700,000,000 Issued shares 373,161,327 372,852,311 Outstanding shares 371,970,655 371,731,551
Summary of preferred stock activity	Three Months Ended March 31, 2018 March 31, 2017 Weighted Avg. Weighted Avg. Shares Dividend Rate Shares Dividend Rate Beginning balance 14,370,060 6.500% 25,875,000 6.500% Shares redeemed - 0.000% (11,500,000) 6.500% Shares converted (95) 6.500% - 0.000% Ending balance 14,369,965 6.500% 14,375,000 6.500%
Summary of common stock issuances	Shares Issued Average Price Gross Proceeds Net Proceeds 2017 Dividend reinvestment plan issuances 1,284,719 $ 68.33 $ 87,985 $ 87,784 2017 Option exercises 156,675 52.71 8,258 8,258 2017 Equity shelf program issuances 338,486 69.75 23,776 23,609 2017 Stock incentive plans, net of forfeitures 181,600 - - 2017 Totals 1,961,480 $ 120,019 $ 119,651 2018 Dividend reinvestment plan issuances 129,975 $ 55.51 $ 7,214 $ 7,214 2018 Preferred stock conversions 83 - - 2018 Stock incentive plans, net of forfeitures 109,046 - - 2018 Totals 239,104 $ 7,214 $ 7,214
Summary of dividend payments	Three Months Ended March 31, 2018 March 31, 2017 Per Share Amount Per Share Amount Common Stock $ 0.8700 $ 323,726 $ 0.8700 $ 315,415 Series I Preferred Stock 0.8125 11,676 0.8125 11,680 Series J Preferred Stock - - 0.2347 2,699 Totals $ 335,402 $ 329,794
Summary of accumulated other comprehensive income/(loss)	Unrecognized gains (losses) related to: Foreign Currency Translation Available for Sale Securities Actuarial Losses Cash Flow Hedges Total Balance at December 31, 2017 $ (110,581) $ - $ (884) $ - $ (111,465) Other comprehensive income before reclassification adjustments 20,212 - - - 20,212 Net current-period other comprehensive income 20,212 - - - 20,212 Balance at March 31, 2018 $ (90,369) $ - $ (884) $ - $ (91,253) Balance at December 31, 2016 $ (173,496) $ 5,120 $ (1,153) $ (2) $ (169,531) Other comprehensive income before reclassification adjustments 2,900 (10,569) - - (7,669) Net current-period other comprehensive income 2,900 (10,569) - - (7,669) Balance at March 31, 2017 $ (170,596) $ (5,449) $ (1,153) $ (2) $ (177,200)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share (Tables) [Abstract]
Computation of basic and diluted earnings per share	Three Months Ended March 31, 2018 2017 Numerator for basic and diluted earnings per share - net income (loss) attributable to common stockholders $ 437,671 $ 312,639 Denominator for basic earnings per share - weighted average shares 371,426 362,534 Effect of dilutive securities: Employee stock options 15 70 Non-vested restricted shares 720 397 Redeemable shares 1,096 1,651 Dilutive potential common shares 1,831 2,118 Denominator for diluted earnings per share - adjusted weighted average shares 373,257 364,652 Basic earnings per share $ 1.18 $ 0.86 Diluted earnings per share $ 1.17 $ 0.86

Disclosure about Fair Value o40

Disclosure about Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure about Fair Value of Financial Instruments (Tables) [Abstract]
Carrying amounts and estimated fair values of financial instruments	March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Mortgage loans receivable $ 264,948 $ 271,887 $ 306,120 $ 332,508 Other real estate loans receivable 102,874 108,850 121,379 125,480 Available-for-sale equity investments 14,443 14,443 7,269 7,269 Cash and cash equivalents 202,824 202,824 243,777 243,777 Restricted cash 61,295 61,295 65,526 65,526 Foreign currency forward contracts 28,713 28,713 15,604 15,604 Financial liabilities: Borrowings under unsecured credit facilities $ 865,000 $ 865,000 $ 719,000 $ 719,000 Senior unsecured notes 7,924,340 8,582,136 8,331,722 9,168,432 Secured debt 2,488,652 2,465,270 2,608,976 2,641,997 Foreign currency forward contracts 58,190 58,190 38,654 38,654 Redeemable OP unitholder interests $ 97,476 $ 97,476 $ 97,476 $ 97,476
The Market approach utilized to measure fair value of financial assets and liabilities on recurring basis	Fair Value Measurements as of March 31, 2018 Total Level 1 Level 2 Level 3 Available-for-sale equity investments $ 14,443 $ 14,443 $ - $ - Foreign currency forward contracts, net asset (liability) (1) (29,477) - (29,477) - Redeemable OP unitholder interests 97,476 - 97,476 - Totals $ 82,442 $ 14,443 $ 67,999 $ - (1) Please see Note 11 for additional information.

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting (Tables) [Abstract]
Summary of information for reportable segments	Three Months Ended March 31, 2018: Triple-net Seniors Housing Operating Outpatient Medical Non-segment / Corporate Total Rental income $ 206,831 $ - $ 136,538 $ - $ 343,369 Resident fees and services - 735,934 - - 735,934 Interest income 14,551 85 12 - 14,648 Other income 1,377 1,148 121 368 3,014 Total revenues 222,759 737,167 136,671 368 1,096,965 Property operating expenses 21 511,941 44,503 - 556,465 Consolidated net operating income 222,738 225,226 92,168 368 540,500 Interest expense 3,442 16,935 1,676 100,722 122,775 Loss (gain) on derivatives and financial instruments, net (7,173) - - - (7,173) Depreciation and amortization 56,032 125,769 46,400 - 228,201 General and administrative - - - 33,705 33,705 Loss (gain) on extinguishment of debt, net (32) (189) 11,928 - 11,707 Impairment of assets 25,884 2,301 - - 28,185 Other expenses 1,120 (188) 598 2,182 3,712 Income (loss) from continuing operations before income taxes and income from unconsolidated entities 143,465 80,598 31,566 (136,241) 119,388 Income tax (expense) benefit (1,136) 162 (428) (186) (1,588) Income (loss) from unconsolidated entities 5,821 (9,480) 1,230 - (2,429) Income (loss) from continuing operations 148,150 71,280 32,368 (136,427) 115,371 Gain (loss) on real estate dispositions, net 123,397 5 214,782 - 338,184 Net income (loss) $ 271,547 $ 71,285 $ 247,150 $ (136,427) $ 453,555 Total assets $ 8,937,964 $ 13,769,265 $ 4,911,566 $ 127,864 $ 27,746,659 Three Months Ended March 31, 2017: Triple-net Seniors Housing Operating Outpatient Medical Non-segment / Corporate Total Rental income $ 227,290 $ - $ 139,851 $ - $ 367,141 Resident fees and services - 670,337 - - 670,337 Interest income 20,679 69 - - 20,748 Other income 1,766 1,461 612 233 4,072 Total revenues 249,735 671,867 140,463 233 1,062,298 Property operating expenses - 462,425 47,744 - 510,169 Consolidated net operating income 249,735 209,442 92,719 233 552,129 Interest expense 5,511 15,816 2,291 94,979 118,597 Loss (gain) on derivatives and financial instruments, net 1,224 - - - 1,224 Depreciation and amortization 59,608 119,737 48,931 - 228,276 General and administrative - - - 31,101 31,101 Loss (gain) on extinguishment of debt, net 29,084 890 1,382 - 31,356 Impairment of assets - 5,406 5,625 - 11,031 Other expenses 5,010 1,778 360 4,527 11,675 Income (loss) from continuing operations before income taxes and income from unconsolidated entities 149,298 65,815 34,130 (130,374) 118,869 Income tax (expense) benefit (800) (1,087) (335) (23) (2,245) Income (loss) from unconsolidated entities 5,638 (29,191) (1) 447 - (23,106) Income (loss) from continuing operations 154,136 35,537 34,242 (130,397) 93,518 Gain (loss) on real estate dispositions, net 231,081 13,011 - - 244,092 Net income (loss) $ 385,217 $ 48,548 $ 34,242 $ (130,397) $ 337,610 (1) Primarily due to the recognition of goodwill and intangible asset impairments on unconsolidated joint ventures, as well as non-recurring income tax expense. Three Months Ended March 31, 2018 March 31, 2017 Revenues: Amount % Amount % United States $ 863,789 78.8% $ 858,668 80.9% United Kingdom 116,525 10.6% 93,843 8.8% Canada 116,651 10.6% 109,787 10.3% Total $ 1,096,965 100.0% $ 1,062,298 100.0% As of March 31, 2018 December 31, 2017 Assets: Amount % Amount % United States $ 21,847,420 78.7% $ 22,274,443 79.7% United Kingdom 3,397,904 12.3% 3,239,039 11.6% Canada 2,501,335 9.0% 2,430,963 8.7% Total $ 27,746,659 100.0% $ 27,944,445 100.0%

Variable Interest Entity Disc42

Variable Interest Entity Disclosure (Tables)	3 Months Ended
	Mar. 31, 2018
Variable Interest Entity Disclosure [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	March 31, 2018 December 31, 2017 Assets Net real property owned $ 993,156 $ 1,002,137 Cash and cash equivalents 16,871 12,308 Receivables and other assets 17,198 16,330 Total assets (1) $ 1,027,225 $ 1,030,775 Liabilities and equity Secured debt $ 469,757 $ 471,103 Accrued expenses and other liabilities 16,501 14,832 Redeemable noncontrolling interests 171,035 171,898 Total equity 369,932 372,942 Total liabilities and equity $ 1,027,225 $ 1,030,775 (1) Note that assets of the consolidated VIEs can only be used to settle obligations relating to such VIEs. Liabilities of the consolidated VIEs represent claims against the specific assets of the VIEs.

Accounting Policies and Relat43

Accounting Policies and Related Matters (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies and Related Matters [Abstract]
Loss (gain) on derivatives and financial instruments, net	$ 7,173	$ (1,224)

Accounting Policies and Relat44

Accounting Policies and Related Matters (Details 2) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Accounting Policies and Related Matters [Line Items]
Cash disbursed for acquisitions		$ (405,609)	$ (102,356)
Decrease (increase) in restricted cash		0	0
Net cash provided from (used in) investing activities		421,077	920,174
Increase (decrease) in cash and cash equivalents		(45,184)	(184,083)
Cash and cash equivalents at beginning of period		243,777	607,220
Cash and cash equivalents at end of period		$ 202,824	423,137
As Previously Reported
Accounting Policies and Related Matters [Line Items]
Cash disbursed for acquisitions			(102,356)
Decrease (increase) in restricted cash			145,065
Net cash provided from (used in) investing activities			1,065,239
Increase (decrease) in cash and cash equivalents	[1]		(39,018)
Cash and cash equivalents at beginning of period	[1]		419,378
Cash and cash equivalents at end of period	[1]		380,360
Accounting Standards Update 2016-18 [Member] | As Reported
Accounting Policies and Related Matters [Line Items]
Cash disbursed for acquisitions			(102,356)
Decrease (increase) in restricted cash			0
Net cash provided from (used in) investing activities			920,174
Increase (decrease) in cash and cash equivalents	[1]		(184,083)
Cash and cash equivalents at beginning of period	[1]		607,220
Cash and cash equivalents at end of period	[1]		$ 423,137
[1]	Amounts in As Reported column include cash and cash equivalents and restricted cash as required. Amounts in the As Previously Reported column reflect only cash and cash equivalents.

Real Property Acquisitions an45

Real Property Acquisitions and Development (Details 1) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Triple Net [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements		$ 1,691	$ 4,017
Buildings and improvements		235	37,241
Total assets acquired		1,926	41,258
Accrued expenses and other liabilities		(6)	0
Total liabilities assumed		(6)	0
Cash disbursed for acquisitions	[1]	1,920	41,258
Construction in progress additions		15,850	46,754
Less: Capitalized Interest		(847)	(2,028)
Less: Foreign currency translation		0	(164)
Cash disbursed for construction in progress		15,003	44,562
Capital improvements to existing properties		2,351	10,495
Total cash invested in real property		19,274	96,315
Senior housing - operating [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements		35,193	4,304
Buildings and improvements		372,562	44,075
Acquired lease intangibles		48,805	1,741
Receivables and other assets		265	74
Total assets acquired	[2]	456,825	50,194
Secured debt		(89,973)	0
Accrued expenses and other liabilities		(12,808)	(2,755)
Total liabilities assumed		(102,781)	(2,755)
Noncontrolling interests		(5,618)	(647)
Non-cash acquisition related activity	[3]	0	(14,148)
Cash disbursed for acquisitions		348,426	32,644
Construction in progress additions		10,562	8,062
Less: Capitalized Interest		(891)	(1,707)
Less: Foreign currency translation		(5,032)	691
Cash disbursed for construction in progress		4,639	7,046
Capital improvements to existing properties		31,325	24,254
Total cash invested in real property		384,390	63,944
Cash Acquired from Acquisition		2,155	400
Non Cash Acquisition Financed As Real Estate Loan Receivable			6,349
Non cash acquisition financed as equity investments			7,799
Outpatient Medical [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements		7,369	2,895
Buildings and improvements		42,673	23,310
Acquired lease intangibles		5,852	3,496
Receivables and other assets		1	3
Total assets acquired	[4]	55,895	29,704
Accrued expenses and other liabilities		(632)	(1,250)
Total liabilities assumed		(632)	(1,250)
Cash disbursed for acquisitions		55,263	28,454
Construction in progress additions		2,803	14,921
Less: Capitalized Interest		(598)	(717)
Less: Accruals	[5]	888	3,522
Cash disbursed for construction in progress		3,093	17,726
Capital improvements to existing properties		12,871	7,366
Total cash invested in real property		71,227	53,546
Cash Acquired from Acquisition		$ 1,950	$ 0
[1]	Primarily reprsents land acquired on an existing property during the three months ended March 31, 2018.
[2]	Excludes $2,155,000 and $400,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018 and 2017, respectively.
[3]	Includes $6,349,000 related to the acquisition of assets previously financed as real estate loans receivable and $7,799,000 previously financed as an investment in an unconsolidated entity during the three months ended March 31, 2017.
[4]	Excludes $1,950,000 of unrestricted and restricted cash acquired during the three months ended March 31, 2018.
[5]	Represents non-cash accruals for amounts to be paid in future periods for properties that converted, off-set by amounts paid in the current period.

Real Property Acquisitions an46

Real Property Acquisitions and Development (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Development projects:
Total development projects	$ 85,977	$ 187,004
Total construction in progress conversions	85,977	187,004
Triple Net [Member]
Development projects:
Total development projects	49,759	157,460
Seniors housing operating [Member]
Development projects:
Total development projects	36,218	3,634
Outpatient Medical [Member]
Development projects:
Total development projects	$ 0	$ 25,910

Real Estate Intangibles (Detail

Real Estate Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Intangible Assets:
Gross historical cost	$ 1,548,621	$ 1,502,471
Accumulated amortization	(1,149,223)	(1,125,437)
Net book value	$ 399,398	$ 377,034
Weighted-average amortization period in years	14 years 5 months	15 years 1 month
Intangible Liabilities:
Gross historical cost	$ 80,246	$ 68,970
Accumulated amortization	(40,400)	(39,629)
Net book value	$ 39,846	$ 29,341
Weighted-average amortization period in years	15 years 12 months	20 years 1 month
In place lease intangibles [Member]
Intangible Assets:
Gross historical cost	$ 1,395,920	$ 1,352,139
Above market tenant leases [Member]
Intangible Assets:
Gross historical cost	58,402	58,443
Below market ground leases [Member]
Intangible Assets:
Gross historical cost	59,030	58,784
Lease commissions [Member]
Intangible Assets:
Gross historical cost	35,269	33,105
Below market tenant leases [Member]
Intangible Liabilities:
Gross historical cost	71,706	60,430
Above market ground leases [Member]
Intangible Liabilities:
Gross historical cost	$ 8,540	$ 8,540

Real Estate Intangibles (Real E

Real Estate Intangibles (Real Estate Intangible Maturity Schedule) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Estimated Aggregate Amortization Expense For Acquired Lease Intangibles Expected To Be Recognized [Line Items]
Totals	$ 399,398	$ 377,034
Intangible Liability [Member]
Estimated Aggregate Amortization Expense For Acquired Lease Intangibles Expected To Be Recognized [Line Items]
2,018	4,470
2,019	5,582
2,020	5,085
2,021	4,597
2,022	4,132
Thereafter	15,980
Totals	39,846
Intangible Asset [Member]
Estimated Aggregate Amortization Expense For Acquired Lease Intangibles Expected To Be Recognized [Line Items]
2,018	94,521
2,019	74,771
2,020	47,871
2,021	20,985
2,022	17,770
Thereafter	143,480
Totals	$ 399,398

Real Estate Intangibles (Deta49

Real Estate Intangibles (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ (351)	$ 304
Property operating expenses related to above/below market ground leases, net	367	(312)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (32,261)	$ (39,302)

Dispositions, Assets Held for50

Dispositions, Assets Held for Sale and Discontinued Operations (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)properties	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Real property dispositions:
Total dispositions	$ 548,936	$ 822,049
Gain (loss) on sale of properties	338,184	244,092
Net other assets/liabilities disposed	5,089	20,933
Proceeds from sales of real property	892,209	1,087,074
Net Real Estate Investments	25,941,125		$ 26,171,077
Asset Impairment Charges	28,185	11,031
Triple Net [Member]
Real property dispositions:
Total dispositions	$ 323,667	808,204
Number of properties classified as held for sale | properties	36
Asset Impairment Charges	$ 25,884	0
Senior housing - operating [Member]
Real property dispositions:
Total dispositions	$ 2,200	13,845
Number of properties classified as held for sale | properties	7
Asset Impairment Charges	$ 2,301	5,406
Outpatient Medical [Member]
Real property dispositions:
Total dispositions	$ 223,069	0
Number of properties classified as held for sale | properties	2
Asset Impairment Charges	$ 0	$ 5,625
Held for sale
Real property dispositions:
Net Real Estate Investments	$ 368,249

Dispositions, Assets Held for51

Dispositions, Assets Held for Sale and Discontinued Operations (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Rental income, disposed	$ 13,886	$ 43,787
Expenses:
Interest expense, disposed	127	2,707
Property operating expenses, disposed	7,256	8,521
Provision for depreciation, disposed	1,741	9,813
Expenses, disposed	9,124	21,041
Income (loss) from disposed properties	$ 4,762	$ 22,746

Real Estate Loans Receivable (D

Real Estate Loans Receivable (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Advances on real estate loans receivable:
Investments in new loans		$ 15,436	$ 7,828
Draws on existing loans		12,111	17,547
Net cash advances on real estate loans		27,547	25,375
Receipts on real estate loans receivable:
Loan payoffs		58,557	74,974
Principal payments on loans		32,174	667
Sub-total		90,731	75,641
Less : Non-cash activity	[1]	0	(66,849)
Total receipts on real estate loans		90,731	8,792
Net advances (receipts) on real estate loans		(63,184)	16,583
Triple Net [Member]
Advances on real estate loans receivable:
Investments in new loans		1,172	7,828
Draws on existing loans		12,111	17,547
Net cash advances on real estate loans		13,283	25,375
Receipts on real estate loans receivable:
Loan payoffs		58,557	14,474
Principal payments on loans		32,174	667
Sub-total		90,731	15,141
Less : Non-cash activity	[1]	0	(6,349)
Total receipts on real estate loans		90,731	8,792
Net advances (receipts) on real estate loans		(77,448)	16,583
Senior housing - operating [Member]
Advances on real estate loans receivable:
Investments in new loans		11,806	0
Draws on existing loans		0	0
Net cash advances on real estate loans		11,806	0
Receipts on real estate loans receivable:
Loan payoffs		0	0
Principal payments on loans		0	0
Sub-total		0	0
Less : Non-cash activity	[1]	0	0
Total receipts on real estate loans		0	0
Net advances (receipts) on real estate loans		11,806	0
Outpatient Medical [Member]
Advances on real estate loans receivable:
Investments in new loans		2,458	0
Draws on existing loans		0	0
Net cash advances on real estate loans		2,458	0
Receipts on real estate loans receivable:
Loan payoffs		0	60,500
Principal payments on loans		0	0
Sub-total		0	60,500
Less : Non-cash activity	[1]	0	(60,500)
Total receipts on real estate loans		0	0
Net advances (receipts) on real estate loans		$ 2,458	$ 0
[1]	Triple-net represents acquisitions of assets previously financed as real estate loans. Please see Note 3 for additional information. Outpatient medical represents a deed in lieu of foreclosure on a previously financed first mortgage property.

Real Estate Loans Receivable 53

Real Estate Loans Receivable (Details 1) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Summary of loan impairments
Balance of impaired loans at end of period		$ 214,896	$ 317,049
Allowance for loan losses		68,372	6,196
Balance of impaired loans not reserved		146,524	310,853
Average impaired loans for the period		265,973	340,920
Interest recognized on impaired loans	[1]	$ 5,327	$ 8,243
[1]	Represents cash interest recognized in the period since loans were identified as impaired.

Real Estate Loans Receivable 54

Real Estate Loans Receivable (Textuals) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Financing Receivable, Modifications [Line Items]
Maturity Date	May 13, 2021
Allowance for loan losses	$ 68,372	$ 68,372		$ 6,196
Genesis Healthcare Loans [Member] | Triple Net [Member]
Financing Receivable, Modifications [Line Items]
Provision For Loan And Lease Losses Real Estate Excluding Write Off		$ 62,966	$ 6,935

Investments in Unconsolidated55

Investments in Unconsolidated Entities (Summary of Investments in Unconsolidated Entities) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities		$ 440,424	$ 445,585
Triple Net [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities		$ 22,440	$ 22,856
Triple Net [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	10.00%	10.00%
Triple Net [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	49.00%	49.00%
Seniors Housing Facilities Operating [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities		$ 338,154	$ 352,430
Seniors Housing Facilities Operating [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	10.00%	10.00%
Seniors Housing Facilities Operating [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	50.00%	50.00%
Outpatient Medical [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	43.00%	43.00%
Investments in unconsolidated entities		$ 79,830	$ 70,299
[1]	Excludes in-substance real estate investments.

Investments in Unconsolidated56

Investments in Unconsolidated Entities (Details)	Mar. 31, 2018USD ($)
Schedule of Equity Method Investments [Line Items]
Unamortized Investment In Joint Venture Primarily Attributable To Real Estate And Related Intangible Assets	$ 108,549,000
Sunrise Senior Living Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Unamortized Investment In Joint Venture Primarily Attributable To Real Estate And Related Intangible Assets	$ 108,549,000

Credit Concentration (Details)

Credit Concentration (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2018USD ($)properties		Mar. 31, 2017USD ($)	Dec. 31, 2017
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	1,257
Percent of NOI	[1],[2]	100.00%
Net Operating Income | $		$ 540,500	[3]	$ 552,129
Credit Concentration (Textual) [Abstract]
Percentage total investments with top five customers					41.00%
Sunrise Senior Living Inc. [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1],[4]	160
Sunrise Senior Living Inc. [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2],[4]	15.00%
Net Operating Income | $	[1],[4]	$ 79,838
Revera [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1],[4]	98
Revera [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2],[4]	7.00%
Net Operating Income | $	[1],[4]	$ 39,525
Brookdale [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	137
Brookdale [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	7.00%
Net Operating Income | $	[1]	$ 36,865
Genesis HealthCare [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	86
Genesis HealthCare [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	6.00%
Net Operating Income | $	[1]	$ 34,773
Benchmark Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	48
Benchmark Senior Living [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	4.00%
Net Operating Income | $	[1]	$ 23,948
Remaining Portfolio [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	728
Remaining Portfolio [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	61.00%
Net Operating Income | $	[1]	$ 325,551
[1]	Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments.
[2]	NOI with our top five relationships comprised 41% of total NOI for the year ended December 31, 2017.
[3]	Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments.
[4]	Revera owns a controlling interest in Sunrise Senior Living.

Borrowings Under Credit Facil58

Borrowings Under Credit Facilities and Related Items (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018		Mar. 31, 2017		Dec. 31, 2017
Aggregate borrowings under the unsecured line of credit arrangements
Balance outstanding at quarter end	$ 865,000	[1]	$ 522,000	[1]	$ 719,000
Maximum amount outstanding at any month end	865,000		1,010,000
Average amount outstanding (total of daily principal balances divided by days in period)	$ 364,111		$ 796,356
Weighted average interest rate (actual interest expense divided by average borrowings outstanding)	2.72%		1.81%
[1]	As of March 31, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.

Borrowings Under Credit Facil59

Borrowings Under Credit Facilities and Related Items (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)properties
Line Of Credit Facility [Line Items]
Unsecured line of credit arrangement	$ 3,000,000
Number of banks in consortium | properties	29
Available to borrow in alternate currencies	$ 1,000,000
Annual facility fee for each bank based on commitment amount	0.15%
Maturity Date	May 13, 2021
Term Loan Interest Rate Margin	0.90%
HCN Term Loan	$ 500,000
HCN Canadian Denomiated Term Loan	250,000
Accordion Feature [Member]
Line Of Credit Facility [Line Items]
HCN Term Loan	1,000,000
HCN Canadian Denomiated Term Loan	$ 250,000
Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Agent bank's prime rate of interest	2.78%
Maturity Date	May 13, 2020
Letter of credit that reduces the borrowing capacity	$ 22,365

Senior Unsecured Notes and Se60

Senior Unsecured Notes and Secured Debt (Details) £ in Thousands, $ in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2018CAD ($)	Mar. 31, 2018GBP (£)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Principal payments due on debt obligations
2,018				$ 350,257
2,019				1,083,773
2,020	[1]			828,289
2,021	[2],[3]			1,372,804
2,022				824,905
Thereafter	[4],[5]			6,045,356
Totals				10,505,384
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Senior unsecured notes				7,924,340	$ 8,331,722
Secured debt				2,488,652	$ 2,608,976
Maturity Date		May 13, 2021
Senior Unsecured Notes [Member]
Principal payments due on debt obligations
2,018	[6],[7]			0
2,019	[6],[7]			600,000
2,020	[1],[6],[7]			690,220
2,021	[2],[3],[6],[7]			1,143,934
2,022	[6],[7]			600,000
Thereafter	[4],[5],[6],[7]			4,972,835
Totals	[6],[7]			$ 8,006,989
Senior Unsecured Notes [Member] | Maximum [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		6.50%	6.50%	6.50%
Senior Unsecured Notes [Member] | Minimum [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		2.40%	2.40%	2.40%
Secured Debt [Member]
Principal payments due on debt obligations
2,018	[6],[8]			$ 350,257
2,019	[6],[8]			483,773
2,020	[1],[6],[8]			138,069
2,021	[2],[3],[6],[8]			228,870
2,022	[6],[8]			224,905
Thereafter	[4],[5],[6],[8]			1,072,521
Totals	[6],[8]			2,498,395
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Carrying values of properties securing the debt				$ 5,272,358
Secured Debt [Member] | Maximum [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		7.93%	7.93%	7.93%
Secured Debt [Member] | Minimum [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		1.69%	1.69%	1.69%
3.35% senior unsecured note due 2020
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Senior unsecured notes issued amount		$ 300,000		$ 232,720
Debt Instrument, Issuance Date		Nov. 1, 2015
Maturity Date		Nov. 1, 2020
Canadian Denominated Unsecured Term Loan [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Senior unsecured notes		$ 250,000		193,934
Debt Instrument Basis Spread On Variable Rate1		2.55%
Debt Instrument, Issuance Date		May 13, 2016
Maturity Date		May 13, 2021
Canadian Denominated Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Debt Instrument Basis Spread On Variable Rate1		0.95%
Unsecured term credit facility [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Senior unsecured notes				$ 500,000
Debt Instrument Basis Spread On Variable Rate1		2.70%
Debt Instrument, Issuance Date		May 13, 2016
Maturity Date		May 13, 2021
Unsecured term credit facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Debt Instrument Basis Spread On Variable Rate1		0.95%
UK Debt Due 2028 [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		4.80%	4.80%	4.80%
Senior unsecured notes issued amount			£ 550,000	$ 771,485
Debt Instrument, Issuance Date		Nov. 20, 2013
Maturity Date		Nov. 20, 2028
UK Debt Due 2034 [Member]
Senior Unsecured Notes and Secured Debt (Textual) [Abstract]
Interest rate		4.50%	4.50%	4.50%
Senior unsecured notes issued amount			£ 500,000	$ 701,350
Debt Instrument, Issuance Date		Nov. 25, 2014
Maturity Date		Nov. 24, 2034
[1]	In November 2015, one of our wholly-owned subsidiaries issued and we guaranteed $300,000,000 of Canadian-denominated 3.35% senior unsecured notes due 2020 (approximately $232,720,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018).
[2]	On May 13, 2016, we refinanced the funding on a $250,000,000 Canadian-denominated unsecured term credit facility (approximately $193,934,000 based on the Canadian/U.S. Dollar exchange rate on March 31, 2018). The loan matures on May 13, 2021 and bears interest at the Canadian Dealer Offered Rate plus 95 basis points (2.55% at March 31, 2018).
[3]	On May 13, 2016, we refinanced the funding on a $500,000,000 unsecured term credit facility. The loan matures on May 13, 2021 and bears interest at LIBOR plus 95 basis points (2.7% at March 31, 2018).
[4]	On November 20, 2013, we completed the sale of £550,000,000 (approximately $771,485,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.8% senior unsecured notes due 2028.
[5]	On November 25, 2014, we completed the sale of £500,000,000 (approximately $701,350,000 based on the Sterling/U.S. Dollar exchange rate in effect on March 31, 2018) of 4.5% senior unsecured notes due 2034.
[6]	Amounts represent principal amounts due and do not include unamortized premiums/discounts, debt issuance costs, or other fair value adjustments as reflected on the balance sheet.
[7]	Annual interest rates range from 2.4% to 6.5%.
[8]	Annual interest rates range from 1.69% to 7.93%. Carrying value of the properties securing the debt totaled $5,272,358,000 at March 31, 2018.

Senior Unsecured Notes and Se61

Senior Unsecured Notes and Secured Debt (Details 1) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Unsecured note issuances
Senior unsecured debt redeemed	$ 450,000	$ 0
Excluding Fair Value Adjustments [Member]
Unsecured note issuances
Senior unsecured debt balance	8,006,989	8,284,267	$ 8,417,447	$ 8,260,038
Senior unsecured debt extinguished	(450,000)	0
Senior unsecured debt foreign currency	$ 39,542	$ 24,229
Senior unsecured debt balance average rate	0.04451	0.04262	0.04306	0.04245
Senior unsecured debt extinguished average rate	0.0225	0
Senior unsecured debt foreign currency average rate	0.05216	0.04391

Senior Unsecured Notes and Se62

Senior Unsecured Notes and Secured Debt (Details 2) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Secured debt principal activity
Secured debt issued	$ 20,326	$ 12,536
Secured debt extinguished	197,655	822,438
Excluding Fair Value Adjustments [Member]
Secured debt principal activity
Secured debt principal balance	2,498,395	2,665,477	$ 2,618,408	$ 3,465,066
Secured debt issued	20,326	12,536
Secured debt assumed	85,192	0
Secured debt extinguished	(183,408)	(806,189)
Secured debt foreign currency	(27,876)	10,313
Secured debt principal payments	$ (14,247)	$ (16,249)
Secured debt principal balance average rate	0.03696	0.03744	0.03761	0.04094
Secured debt principal issued average rate	0.03774	0.0234
Secured debt principal assumed average rate	0.04395	0
Secured debt principal extinguished average rate	0.05809	0.0558
Secured debt principal foreign currency average rate	0.03326	0.03262
Secured debt principal payment average rate	0.03865	0.04469

Derivative Instrument (Notional

Derivative Instrument (Notional Table) (Details) £ in Thousands, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018CAD ($)	Mar. 31, 2018GBP (£)	Dec. 31, 2017CAD ($)	Dec. 31, 2017GBP (£)	Mar. 31, 2018GBP (£)	Dec. 31, 2017GBP (£)
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	$ 18,000		$ 36,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	575,000		575,000		£ 550,000	£ 550,000
Notional Amount Of Nonderivative Instruments	250,000	£ 1,050,000	250,000	£ 1,050,000
Not Designated as Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	$ 408,007		$ 408,007		£ 0	£ 80,000

Derivative Instruments (Details

Derivative Instruments (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest Rate Swap [Member]
Derivative [Line Items]
Gain (loss) on forward exchange contracts recognized in income.	$ 1,195	$ 2,457
Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain on Release of cumulative translation adjustment related to net investment hedge of an equity investment	$ (62,698)	$ (44,341)

Derivative Instruments (Textual

Derivative Instruments (Textual) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments [Abstract]
Derivative Cash Received On Hedge	$ (8,055)	$ 8,218

Commitments and Contingencies (

Commitments and Contingencies (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Number	Dec. 31, 2017USD ($)
Commitments and Contingencies (Textual) [Abstract]
Number of outstanding letters of credit | Number	14
Letter of credit obligation	$ 158,969
Line Of Credit Facility [Line Items]
Outstanding construction financings for leased properties	180,984	$ 237,746
Additional financing to complete construction	392,710
Total contingent purchase obligations	$ 10,350
Minimum part of economic life of the leased asset to be classified as capital lease	75.00%
Minimum net present value of the future minimum lease payments to be classified as capital lease.	90.00%
Operating lease obligations relating to certain ground leases	$ 1,121,736
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	76,388
Capital Leases, Future Minimum Payments Due	$ 87,922
Letter Of Credit Expiration Date Maximum	Dec. 31, 2024
Letter Of Credit Expiration Date Minimum	Jan. 1, 2018

Stockholder's Equity (Details)

Stockholder's Equity (Details) - shares	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Preferred Stock:
Authorized shares	50,000,000	50,000,000
Issued shares	14,375,000	14,375,000
Outstanding shares	14,369,965	14,370,060	14,375,000	25,875,000
Common Stock, $1.00 par value:
Authorized shares	700,000,000	700,000,000
Issued shares	373,161,327	372,852,311
Outstanding shares	371,970,655	371,731,551

Stockholder's Equity (Details 1

Stockholder's Equity (Details 1)	3 Months Ended
	Mar. 31, 2018USD ($)shares	Mar. 31, 2017USD ($)$ / sharesshares
Summary of common stock issuances
Equity shelf plan issuances, Shares Issued | shares		338,486
Equity shelf plan issuances, average price | $ / shares		69.75
Equity Shelf Plan Issuances Gross Proceeds		$ 23,776,000
Equity Shelf Plan Issuances Net Proceeds		$ 23,609,000
Preferred stock conversions | shares	83
Dividend reinvestment plan issuances, Shares Issued | shares	129,975	1,284,719
Dividend reinvestment plan issuances, Average Price	55.51	68.33
Dividend reinvestment plan issuances, Net Proceeds	$ 7,214,000	$ 87,784,000
Dividend reinvestment plan issuances, Gross Proceeds	$ 7,214,000	$ 87,985,000
Option exercises, Shares | shares		156,675
Option exercises, Average Price		52.71
Option exercises, Gross Proceeds		$ 8,258,000
Option exercises, Net Proceeds		$ 8,258,000
Stock incentive plans, net of forfeitures, Shares Issued | shares	109,046	181,600
Issuance of Common Stock, Shares | shares	239,104	1,961,480
Gross Proceeds From Issuance of Common Stock	$ 7,214,000	$ 120,019,000
Net proceeds from the issuance of common stock	$ 7,214,000	$ 119,651,000

Stockholder's Equity (Details 2

Stockholder's Equity (Details 2) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Summary of accumulated other comprehensive income/(loss) [Line Items]
Unrecognized gains (losses) on foreign currency translation	$ (90,369)	$ (110,581)	$ (170,596)	$ (173,496)
Unrecognized losses on equity investments	0	0	(5,449)	5,120
Unrecognized actuarial losses	(884)	(884)	(1,153)	(1,153)
Unrecognized losses on cash flow hedges	0	0	(2)	(2)
Totals	(91,253)	$ (111,465)	(177,200)	$ (169,531)
Other comprehensive income before reclassification adjustments
Summary of accumulated other comprehensive income/(loss) [Line Items]
Unrecognized gains (losses) on foreign currency translation	20,212		2,900
Unrecognized losses on equity investments	0		(10,569)
Unrecognized actuarial losses	0		0
Unrecognized losses on cash flow hedges	0		0
Totals	20,212		(7,669)
Net current period other comprehensive income
Summary of accumulated other comprehensive income/(loss) [Line Items]
Unrecognized gains (losses) on foreign currency translation	20,212		2,900
Unrecognized losses on equity investments	0		(10,569)
Unrecognized actuarial losses	0		0
Unrecognized losses on cash flow hedges	0		0
Totals	$ 20,212		$ (7,669)

Stockholder's Equity (Details 3

Stockholder's Equity (Details 3) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Stockholders' Equity (Details) [Abstract]
Preferred Stock, Shares Outstanding	14,369,965	14,375,000	14,370,060	25,875,000
Preferred stock, shares redeemed	0	(11,500,000)
Preferred stock, shares converted	(95)	0
Preferred stock balance weighted average rate	6.50%	6.50%	6.50%	6.50%
Preferred stock balance redeemed weighted average rate	0.00%	6.50%
Preferred stock balance converted average rate	6.50%	0.00%
Preferred stock redemption charge	$ 0	$ 9,769

Stockholder's Equity (Details 5

Stockholder's Equity (Details 5) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Summary of dividend payments
Dividends declared and paid per common share	$ 0.87	$ 0.87
Common stock cash dividends	$ 323,726	$ 315,415
Total dividends paid	$ 335,402	$ 329,794
Series I Preferred Stock [Member]
Summary of dividend payments
Dividends declared and paid per preferred share	$ 0.8125	$ 0.8125
Preferred stock cash dividends	$ 11,676	$ 11,680
Series J Preferred Stock [Member]
Summary of dividend payments
Dividends declared and paid per preferred share	$ 0	$ 0.2347
Preferred stock cash dividends	$ 0	$ 2,699

Stock Incentive Plans (Details

Stock Incentive Plans (Details Textual) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stock Incentive Plans [Line Items]
Number of common stock authorized for 2016 Long-Term Incentive Plan	10,000
Stock-based compensation expense	$ 11,557	$ 4,906
Maximum [Member]
Stock Incentive Plans [Line Items]
Vesting period	5 years
Minimum [Member]
Stock Incentive Plans [Line Items]
Vesting period	3 years
Stock Incentive Plan [Member]
Stock Incentive Plans [Line Items]
Option expiration period	10 years

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Computation of basic and diluted earnings per share
Numerator for basic and diluted earnings per share - net income (loss) attributable to common stockholders	$ 437,671	$ 312,639
Denominator for basic earnings per share - weighted average shares	371,426	362,534
Effect of dilutive securities:
Employee stock options	15	70
Non-vested restricted shares	720	397
Redeemable shares	1,096	1,651
Dilutive potential common shares	1,831	2,118
Denominator for diluted earnings per share - adjusted weighted average shares	373,257	364,652
Basic earnings per share	$ 1.18	$ 0.86
Diluted earnings per share	$ 1.17	$ 0.86

Disclosure about Fair Value o74

Disclosure about Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018		Dec. 31, 2017	Mar. 31, 2017		Dec. 31, 2016
Financial Assets:
Loans receivable, Carrying Amount	$ 436,194		$ 495,871
Loans receivable, Fair value	271,887		332,508
Available-for-sale equity investments, Carrying Amount	14,443		7,269
Available-for-sale equity investments, Fair Value	14,443		7,269
Cash And Cash Equivalents At Carrying Value	202,824		243,777	$ 423,137		$ 607,220
Cash and cash equivalents, Fair Value	202,824		243,777
Restricted cash, Carrying Value	61,295		65,526
Restricted cash, Fair Value	61,295		65,526
Foreign Currency Forward Contracts Carrying Value	28,713		15,604
Foreign Currency Forward Contracts Fair Value	28,713		15,604
Financial Liabilities:
Borrowings under primary unsecured credit facilities, Carrying Value	865,000	[1]	719,000	$ 522,000	[1]
Borrowings under primary unsecured credit facilities, Fair Value	865,000		719,000
Senior unsecured notes, Carrying Amount	7,924,340		8,331,722
Senior unsecured notes, Fair Value	8,582,136		9,168,432
Secured debt, Carrying Amount	2,488,652		2,608,976
Secured debt, Fair Value	2,465,270		2,641,997
Foreign Currency Forward Contracts Carrying Value	58,190		38,654
Foreign Currency Forward Contracts, Fair Value	58,190		38,654
Redeemable OP unitholder interests carrying value	97,476		97,476
Redeemable OP unitholder interests fair value	97,476		97,476
Mortgage Loans on Real Estate [Member]
Financial Assets:
Loans receivable, Carrying Amount	264,948		306,120
Loans receivable, Fair value	271,887		332,508
Other Real Estate Loans Receivable [Member]
Financial Assets:
Loans receivable, Carrying Amount	102,874		121,379
Loans receivable, Fair value	$ 108,850		$ 125,480
[1]	As of March 31, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.

Disclosure about Fair Value o75

Disclosure about Fair Value of Financial Instruments (Details 1) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
The Market approach utilized to measure fair value of financial assets and liabilities on recurring basis
Available-for-sale equity investments		$ 14,443	$ 7,269
Foreign currency forward contracts	[1]	(29,477)
Redeemable OP unitholder interests		97,476
Totals		82,442
Level 1 [Member]
The Market approach utilized to measure fair value of financial assets and liabilities on recurring basis
Available-for-sale equity investments		14,443
Foreign currency forward contracts	[1]	0
Redeemable OP unitholder interests		0
Totals		14,443
Level 2 [Member]
The Market approach utilized to measure fair value of financial assets and liabilities on recurring basis
Available-for-sale equity investments		0
Foreign currency forward contracts	[1]	(29,477)
Redeemable OP unitholder interests		97,476
Totals		67,999
Level 3 [Member]
The Market approach utilized to measure fair value of financial assets and liabilities on recurring basis
Available-for-sale equity investments		0
Foreign currency forward contracts	[1]	0
Redeemable OP unitholder interests		0
Totals		$ 0
[1]	Please see Note 11 for additional information.

Segment Reporting (Details)

Segment Reporting (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)		Mar. 31, 2017USD ($)		Dec. 31, 2017USD ($)
Summary of information for reportable segments
Rental income	$ 343,369		$ 367,141
Resident fees and services	735,934		670,337
Interest income	14,648		20,748
Other income	3,014		4,072
Total revenues	1,096,965		1,062,298
Property operating expenses	556,465		510,169
Net Operating Income from Continuing Operations	540,500	[1]	552,129
Interest expense	122,775		118,597
Loss (gain) on derivatives and financial instruments, net	(7,173)		1,224
Depreciation and amortization	228,201		228,276
General and administrative	33,705		31,101
Loss (gain) on extinguishment of debt, net	11,707		31,356
Impairment of Asset	28,185		11,031
Other expenses	3,712		11,675
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	119,388		118,869
Income tax expense	(1,588)		(2,245)
(Loss) income from unconsolidated entities	(2,429)		(23,106)
Income (loss) from continuing operations	115,371		93,518
Gain (loss) on real estate dispositions, net	338,184		244,092
Net income	453,555		$ 337,610
Total assets	$ 27,746,659				$ 27,944,445
Percent Of Assets	1				1
Percent Of Revenues	1		1
United States
Summary of information for reportable segments
Total revenues	$ 863,789		$ 858,668
Total assets	$ 21,847,420				$ 22,274,443
Percent Of Assets	0.787				0.797
Percent Of Revenues	0.788		0.809
United Kingdom
Summary of information for reportable segments
Total revenues	$ 116,525		$ 93,843
Total assets	$ 3,397,904				$ 3,239,039
Percent Of Assets	0.123				0.116
Percent Of Revenues	0.106		0.088
Canada
Summary of information for reportable segments
Total revenues	$ 116,651		$ 109,787
Total assets	$ 2,501,335				$ 2,430,963
Percent Of Assets	0.09				0.087
Percent Of Revenues	0.106		0.103
Triple Net [Member]
Summary of information for reportable segments
Rental income	$ 206,831		$ 227,290
Resident fees and services	0		0
Interest income	14,551		20,679
Other income	1,377		1,766
Total revenues	222,759		249,735
Property operating expenses	21		0
Net Operating Income from Continuing Operations	222,738		249,735
Interest expense	3,442		5,511
Loss (gain) on derivatives and financial instruments, net	(7,173)		1,224
Depreciation and amortization	56,032		59,608
General and administrative	0		0
Loss (gain) on extinguishment of debt, net	(32)		29,084
Impairment of Asset	25,884		0
Other expenses	1,120		5,010
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	143,465		149,298
Income tax expense	(1,136)		(800)
(Loss) income from unconsolidated entities	5,821		5,638
Income (loss) from continuing operations	148,150		154,136
Gain (loss) on real estate dispositions, net	123,397		231,081
Net income	271,547		385,217
Total assets	8,937,964
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income	0		0
Resident fees and services	735,934		670,337
Interest income	85		69
Other income	1,148		1,461
Total revenues	737,167		671,867
Property operating expenses	511,941		462,425
Net Operating Income from Continuing Operations	225,226		209,442
Interest expense	16,935		15,816
Loss (gain) on derivatives and financial instruments, net	0		0
Depreciation and amortization	125,769		119,737
General and administrative	0		0
Loss (gain) on extinguishment of debt, net	(189)		890
Impairment of Asset	2,301		5,406
Other expenses	(188)		1,778
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	80,598		65,815
Income tax expense	162		(1,087)
(Loss) income from unconsolidated entities	(9,480)		(29,191)	[2]
Income (loss) from continuing operations	71,280		35,537
Gain (loss) on real estate dispositions, net	5		13,011
Net income	71,285		48,548
Total assets	13,769,265
Outpatient Medical [Member]
Summary of information for reportable segments
Rental income	136,538		139,851
Resident fees and services	0		0
Interest income	12		0
Other income	121		612
Total revenues	136,671		140,463
Property operating expenses	44,503		47,744
Net Operating Income from Continuing Operations	92,168		92,719
Interest expense	1,676		2,291
Loss (gain) on derivatives and financial instruments, net	0		0
Depreciation and amortization	46,400		48,931
General and administrative	0		0
Loss (gain) on extinguishment of debt, net	11,928		1,382
Impairment of Asset	0		5,625
Other expenses	598		360
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	31,566		34,130
Income tax expense	(428)		(335)
(Loss) income from unconsolidated entities	1,230		447
Income (loss) from continuing operations	32,368		34,242
Gain (loss) on real estate dispositions, net	214,782		0
Net income	247,150		34,242
Total assets	4,911,566
Corporate, Non-Segment [Member]
Summary of information for reportable segments
Rental income	0		0
Resident fees and services	0		0
Interest income	0		0
Other income	368		233
Total revenues	368		233
Property operating expenses	0		0
Net Operating Income from Continuing Operations	368		233
Interest expense	100,722		94,979
Loss (gain) on derivatives and financial instruments, net	0		0
Depreciation and amortization	0		0
General and administrative	33,705		31,101
Loss (gain) on extinguishment of debt, net	0		0
Impairment of Asset	0		0
Other expenses	2,182		4,527
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	(136,241)		(130,374)
Income tax expense	(186)		(23)
(Loss) income from unconsolidated entities	0		0
Income (loss) from continuing operations	(136,427)		(130,397)
Gain (loss) on real estate dispositions, net	0		0
Net income	(136,427)		$ (130,397)
Total assets	$ 127,864
[1]	Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments.
[2]	Primarily due to the recognition of goodwill and intangible asset impairments on unconsolidated joint ventures, as well as non-recurring income tax expense.

Income Taxes and Distributions

Income Taxes and Distributions (Details)	3 Months Ended
	Mar. 31, 2018
Additional Income Taxes and Distributions (Textuals) [Abstract]
Percentage of taxable income to be distributed to stockholders for federal tax purposes	90.00%
Percentage of capital gains excluded from taxable income distributed to shareholders	100.00%
Percentage of federal excise tax on real estate investment trusts that do not distribute income.	4.00%

Variable Interest Entity Disc78

Variable Interest Entity Disclosure (Details) - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Total assets	[1]	$ 1,027,225	$ 1,030,775
Total equity		369,932	372,942
Total liabilities and equity		1,027,225	1,030,775
Net real property owned [Member]
Variable Interest Entity [Line Items]
Total assets		993,156	1,002,137
Cash and cash equivalents [Member]
Variable Interest Entity [Line Items]
Total assets		16,871	12,308
Receivables and other assets [Member]
Variable Interest Entity [Line Items]
Total assets		17,198	16,330
Secured Debt [Member]
Variable Interest Entity [Line Items]
Liabilities		469,757	471,103
Accrued expenses and other liabilities [Member]
Variable Interest Entity [Line Items]
Liabilities		16,501	14,832
Redeemable noncontrolling interests [Member]
Variable Interest Entity [Line Items]
Liabilities		$ 171,035	$ 171,898
[1]	Note that assets of the consolidated VIEs can only be used to settle obligations relating to such VIEs. Liabilities of the consolidated VIEs represent claims against the specific assets of the VIEs.

Subsequent Events (Details)

Subsequent Events (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 01, 2018USD ($)Number$ / shares	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Subsequent Event [Line Items]
Senior unsecured notes		$ 7,924,340	$ 8,331,722
Investment in joint venture		$ 440,424	$ 445,585
Maturity Date		May 13, 2021
Subsequent Event [Member] | Barclays [Member]
Subsequent Event [Line Items]
Commitment To Unsecured Credit Facility Maximum Borrowing Capacity	$ 1,000,000
Subsequent Event [Member] | ProMedica Member [Member]
Subsequent Event [Line Items]
Joint venture ownership	20.00%
Lessor, Operating Lease, Lease Not yet Commenced, Description	(i) 15-year absolute triple-net master lease with three five-year renewal options; (ii) 8% initial cash rental yield with a year one escalator of 1.375% and 2.75% annual escalator thereafter; and (iii) full corporate guarantee of ProMedica
Lessor, Operating Lease, Lease Not yet Commenced, Term of Contract	15 years
Lessor, Operating Lease, Lease Not yet Commenced, Existence of Option to Extend [true/false]	true
Lease Agreement Number Of Renewal Options | Number	3
Lessor, Operating Lease, Lease Not yet Commenced, Renewal Term	5 years
Lease Agreement Initial Cash Rental Yield	8.00%
Lease Agreement Escalator In Year One	1.375%
Lease Agreement Annual Escalator Thereafter	2.75%
Subsequent Event [Member] | Joint Venture With ProMedica [Member]
Subsequent Event [Line Items]
Joint venture ownership	80.00%
Subsequent Event [Member] | Joint Venture With ProMedica [Member] | ProMedica Member [Member]
Subsequent Event [Line Items]
Joint venture ownership	20.00%
Subsequent Event [Member] | Joint Venture With ProMedica [Member] | Scenario, Forecast [Member]
Subsequent Event [Line Items]
Investment in joint venture	$ 2,200,000
Subsequent Event [Member] | Quality Care Properties Inc [Member]
Subsequent Event [Line Items]
Purchase price per share | $ / shares	$ 20.75
Equity Method Investment, Description of Principal Activities	own the real estate of QCP’s principal tenants, HCR ManorCare and Arden Courts
Subsequent Event [Member] | 4.25% Senior Unsecured Notes Due 2028
Subsequent Event [Line Items]
Interest rate	4.25%
Senior unsecured notes issued amount	$ 550,000
Debt issuance proceeds	$ 545,199
Maturity Date	Dec. 31, 2028