Alexandria Real Estate Equities (ARE) 10-Q 7 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 18, 2014
Document and Entity Information	'	'
Entity Registrant Name	'ALEXANDRIA REAL ESTATE EQUITIES INC.	'
Entity Central Index Key	'0001035443	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	71,749,433
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Investments in real estate, net	$7,030,117	$6,776,914
Cash and cash equivalents	61,701	57,696
Restricted cash	24,519	27,709
Tenant receivables	10,654	9,918
Deferred rent	214,793	190,425
Deferred leasing and financing costs, net	193,621	192,658
Marketable Securities	174,802	140,288
Other assets	105,442	134,156
Total assets	7,815,649	7,529,764
Liabilities, Noncontrolling Interests, and Equity	'	'
Secured notes payable	615,551	708,831
Unsecured senior notes payable	1,048,310	1,048,230
Unsecured senior line of credit	571,000	204,000
Loans Payable to Bank	1,100,000	1,100,000
Accounts Payable and Accrued Liabilities	434,528	435,342
Dividends payable	57,377	54,420
Total liabilities	3,826,766	3,550,823
Commitments and contingencies	'	'
Redeemable noncontrolling interests	14,381	14,444
Alexandria Real Estate Equities, Inc.’s stockholders’ equity:	'	'
Series D cumulative convertible preferred stock	250,000	250,000
Series E cumulative redeemable preferred stock	130,000	130,000
Common stock	713	712
Additional paid-in capital	3,542,334	3,572,281
Accumulated other comprehensive loss	-16,245	-36,204
Alexandria’s stockholders’ equity	3,906,802	3,916,789
Noncontrolling interests	67,700	47,708
Total equity	3,974,502	3,964,497
Total liabilities, noncontrolling interests, and equity	$7,815,649	$7,529,764

Consolidated_Statements_of_Inc

Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended				6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Revenues:	'		'		'		'
Rental	$134,992		$114,493		$265,562		$226,019
Tenant recoveries	40,944		35,869		82,626		71,434
Other Income	466		3,568		4,400		6,560
Total revenues	176,402		153,930		352,588		304,013
Expenses:	'		'		'		'
Rental operations	52,353		46,277		104,860		91,463
General and administrative	13,836		12,455		27,060		24,103
Interest	17,433		15,978		36,556		33,998
Depreciation and amortization	57,314		46,344		107,735		92,173
Gains (Losses) on Extinguishment of Debt	0		560		0		560
Total expenses	140,936		121,614		276,211		242,297
Income from continuing operations	35,466		32,316		76,377		61,716
Income from discontinued operations:	'		'		'		'
(Loss) income from discontinued operations	-147	[1]	249	[1]	-309	[1]	1,086	[1]
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	797		772		797		772
Net income	36,116		33,337		76,865		63,574
Dividends on preferred stock	-6,472		-6,471		-12,943		-12,942
Net income attributable to noncontrolling interests	-1,307		-980		-2,502		-1,962
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	-405		-403		-779		-745
Net Income (Loss) Available to Common Stockholders, Basic	$27,932		$25,483		$60,641		$47,925
Earnings per share attributable to Alexandria’s common stockholders – basic and diluted:	'		'		'		'
Continuing operations	$0.39		$0.38		$0.85		$0.72
Discontinued operations	$0		$0		$0		$0.02
Earnings per share – basic and diluted	$0.39		$0.38		$0.85		$0.74
[1]	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$36,116	$33,337	$76,865	$63,574
Unrealized (losses) gains on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	-2,734	44	16,045	360
Reclassification adjustment for losses (gains) included in net income	406	42	406	-230
Unrealized (losses) gains on marketable securities, net	-2,328	86	16,451	130
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap (losses) gains arising during the period	-2,526	105	-3,914	-28
Reclassification adjustment for amortization of interest expense included in net income	1,123	3,834	4,613	8,142
Unrealized gains on interest rate swap agreements, net	-1,403	3,939	699	8,114
Foreign currency translation gains (losses)	5,915	-20,698	2,809	-23,057
Total other comprehensive income (loss)	2,184	-16,673	19,959	-14,813
Comprehensive income	38,300	16,664	96,824	48,761
Less: comprehensive income attributable to noncontrolling interests	-1,307	-1,008	-2,502	-1,906
Comprehensive income attributable to Alexandria’s common stockholders	$36,993	$15,656	$94,322	$46,855

Consolidated_Statement_of_Chan

Consolidated Statement of Changes in Stockholders' Equity and Noncontrolling Interests (Unaudited) (USD $)	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Redeemable Noncontrolling Interests	Series D Preferred Stock	Series D Preferred Stock	Series E Cumulative Redeemable Preferred Stock	Series E Cumulative Redeemable Preferred Stock
In Thousands, except Share data, unless otherwise specified									Preferred Stock		Preferred Stock
Beginning balance at Dec. 31, 2013	$14,444	'	'	'	'	'	$14,444	'	'	'	'
Beginning balance at Dec. 31, 2013	3,964,497	712	3,572,281	0	-36,204	47,708	'	'	250,000	'	130,000
Beginning balance, common shares at Dec. 31, 2013	'	71,172,197	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'	'	'	'
Net Income	76,333	'	'	74,363	'	1,970	'	'	'	'	'
Total other comprehensive income (loss)	19,959	'	'	'	19,959	0	'	'	'	'	'
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	19,410	'	'	'	'	19,410	'	'	'	'	'
Distributions to noncontrolling interests	-1,388	'	'	'	'	-1,388	'	'	'	'	'
Issuances pursuant to stock plan (in shares)	'	145,884	'	'	'	'	'	'	'	'	'
Issuances pursuant to stock plan	10,458	1	10,457	'	'	'	'	'	'	'	'
Dividends declared on common stock	-101,824	'	'	-101,824	'	'	'	'	'	'	'
Dividends declared on preferred stock	-12,943	'	'	-12,943	'	'	'	'	'	'	'
Distributions in excess of earnings	'	'	-40,404	40,404	'	'	'	'	'	'	'
Increase (Decrease) in Temporary Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Net Income	'	'	'	'	'	'	532	'	'	'	'
Total other comprehensive income (loss)	'	'	'	'	'	'	0	'	'	'	'
Distributions to noncontrolling interests	'	'	'	'	'	'	-595	'	'	'	'
Ending balance at Jun. 30, 2014	14,381	'	'	'	'	'	14,381	'	'	'	'
Ending balance at Jun. 30, 2014	3,974,502	713	3,542,334	0	-16,245	67,700	'	'	250,000	'	130,000
Ending balance, common shares at Jun. 30, 2014	'	71,318,081	'	'	'	'	'	'	'	'	'
Beginning balance at Mar. 31, 2014	'	'	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'	'	'	'
Total other comprehensive income (loss)	2,184	'	'	'	'	'	'	'	'	'	'
Dividends declared on common stock	-51,700	'	'	'	'	'	'	'	'	'	'
Dividends declared on preferred stock	'	'	'	'	'	'	'	-4,400	'	-2,100	'
Ending balance at Jun. 30, 2014	14,381	'	'	'	'	'	'	'	'	'	'
Ending balance at Jun. 30, 2014	$3,974,502	'	'	'	'	'	'	'	$250,000	'	$130,000

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Operating Activities	'	'
Net income	$76,865	$63,574
Depreciation, Depletion and Amortization	107,735	93,575
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Gains (Losses) on Extinguishment of Debt	0	560
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	-797	-772
Loss on sale of real estate	0	121
Amortization of loan fees and costs	5,304	4,813
Amortization of debt premiums/discounts	136	237
Amortization of above and below Market Leases	-1,434	-1,660
Deferred rent	-24,619	-14,437
Stock compensation expense	6,304	7,812
Investment gains	-6,225	-2,666
Investment losses	5,240	529
Changes in operating assets and liabilities:	'	'
Restricted cash	0	392
Tenant receivables	-735	847
Deferred leasing costs	-17,452	-23,109
Other assets	-5,916	6,110
Accounts payable, accrued expenses, and tenant security deposits	85	8,215
Net cash (used in) provided by operating activities	144,491	144,141
Investing Activities	'	'
Proceeds from sale of properties	17,868	101,815
Additions to properties	-210,792	-298,927
Purchase of properties	-97,785	0
Change in restricted cash related to construction projects	5,650	-8,889
Contributions to unconsolidated real estate entity	-1,405	-4,889
Gain (Loss) on Investments	0	-293
Additions to investments	-25,358	-14,833
Proceeds from investments	8,794	9,544
Proceeds from Collection of Notes Receivable	29,851	0
Net cash (used in) provided by investing activities	-273,177	-216,472
Financing Activities	'	'
Borrowings from secured notes payable	77,762	26,114
Repayments of borrowings from secured notes payable	-219,427	-31,436
Proceeds from Issuance of Unsecured Debt	0	495,310
Principal borrowings from unsecured senior line of credit	637,000	305,000
Repayments of borrowings from unsecured senior line of credit	-270,000	-871,000
Repayments of Unsecured Debt	0	-150,000
Change in restricted cash related to financings	1,212	16,634
Deferred financing costs paid	-310	-1,457
Proceeds from Issuance of Common Stock	0	534,469
Dividends paid on common stock	-98,867	-73,932
Dividends paid on preferred stock	-12,943	-12,942
Payments of Distributions to Affiliates	-595	-596
Proceeds from Noncontrolling Interests	19,410	0
Distributions to noncontrolling interests	-1,388	-639
Net cash provided by (used in) financing activities	131,854	235,525
Effect of foreign exchange rate changes on cash and cash equivalents	837	-1,960
Net increase in cash and cash equivalents	4,005	161,234
Cash and cash equivalents at beginning of period	57,696	140,971
Cash and cash equivalents at end of period	61,701	302,205
Supplemental Disclosure of Cash Flow Information	'	'
Cash paid during the period for interest, net of interest capitalized	31,922	29,259
Non-Cash Investing Activities	'	'
Note receivable from sale of real estate	0	38,820
Change in accrued capital expenditures	592	-48,198
Assumption of secured notes payable in connection with purchase of properties	$48,329	$0

Background

Background	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Background	'
	Background
	As used in this quarterly report on Form 10-Q, references to the “Company,” “Alexandria,” “we,” “our,” and “us” refer to Alexandria Real Estate Equities, Inc. and its consolidated subsidiaries.
	Alexandria Real Estate Equities, Inc. (NYSE:ARE), with a total market capitalization of approximately $9.3 billion as of June 30, 2014, and an asset base of 31.4 million square feet, including 17.9 million rentable square feet (“RSF”) of operating and current value-creation projects, as well as an additional 13.5 million square feet in future ground-up development projects, is the largest and leading real estate investment trust (“REIT”) uniquely focused on Class A assets in collaborative science and technology campuses located in urban innovation clusters. Alexandria pioneered this niche in 1994 and has since established a dominant market presence in AAA locations including Greater Boston, the San Francisco Bay Area, San Diego, New York City, Maryland, Seattle, and Research Triangle Park. Alexandria is known for its high-quality and diverse client tenant base. Alexandria is the Landlord of Choice to the Life Science Industry®, and approximately 52% of its total annualized base rent (“ABR”) results from investment-grade client tenants (a REIT industry-leading percentage). Alexandria has a longstanding and proven track record of developing Class A assets clustered in urban collaborative science and technology campuses that provide its client tenants with a highly collaborative, 24/7, live/work/play environment, as well as the critical ability to successfully recruit and retain best-in-class talent. We believe these advantages result in higher occupancy levels, longer lease terms, higher rental income, higher returns, and greater long-term asset value. For additional information on Alexandria, please visit our website at www.are.com.
	Our asset base consisted of the following, as of June 30, 2014:
			Square Feet
	Operating properties		15,804,327
	Development properties		1,879,492
	Redevelopment properties		197,289
	Total operating and current value-creation projects		17,881,108
	Near-term value-creation projects in North America (CIP)		2,474,163
	Future value-creation projects		10,760,108
	Land subject to sale negotiations		262,950
	Total		31,378,329
	Ÿ	Investment-grade client tenants represented approximately 52% of our total ABR;
	Ÿ	Approximately 96% of our leases (on an RSF basis) contained effective annual rent escalations that were either fixed (generally ranging from 3% to 3.5%) or indexed based on a consumer price index or other index;
	Ÿ	Approximately 94% of our leases (on an RSF basis) were triple net leases, requiring client tenants to pay substantially all real estate taxes, insurance, utilities, common area, and other operating expenses (including increases thereto) in addition to base rent and;
	Ÿ	Approximately 93% of our leases (on an RSF basis) provided for the recapture of certain capital expenditures (such as heating, ventilation, and air conditioning (“HVAC”) systems maintenance and/or replacement, roof replacement, and parking lot resurfacing) that we believe would typically be borne by the landlord in traditional office leases.
	Any references to the number of buildings, square footage, number of leases, occupancy, and any amounts derived from these values in the notes to the consolidated financial statements are unaudited and outside the scope of our independent registered public accounting firm’s review of our interim consolidated financial statements in accordance with the standards of the Public Company Accounting Oversight Board.

Basis_of_presentation

Basis of presentation	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of presentation	'
	Basis of presentation
	We have prepared the accompanying interim consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and in conformity with the rules and regulations of the Securities and Exchange Commission (“SEC”).  In our opinion, the interim consolidated financial statements presented herein reflect all adjustments that are necessary to fairly present the interim consolidated financial statements.  The results of operations for the interim period are not necessarily indicative of the results that may be expected for the year ending December 31, 2014.  These consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our annual report on Form 10-K for the year ended December 31, 2013.
	The accompanying consolidated financial statements include the accounts of Alexandria Real Estate Equities, Inc. and its consolidated subsidiaries. All significant intercompany balances and transactions have been eliminated.
	We hold interests, together with certain third parties, in companies that we consolidate in our financial statements. We consolidate the companies because we exercise significant control over major decisions by these entities, such as investment activity and changes in financing.
	Reclassifications
	Certain prior period amounts have been reclassified to conform to the current period presentation for discontinued operations.
	Use of estimates
	The preparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, and equity; the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements; and the amounts of revenues and expenses during the reporting period.  Actual results could materially differ from those estimates.
	Investments in real estate, net, and discontinued operations
	We recognize real estate acquired (including the intangible value of above or below market leases, acquired in-place leases, client tenant relationships, and other intangible assets or liabilities), liabilities assumed, and any noncontrolling interest in an acquired entity at their fair value as of the acquisition date.  If there is a bargain fixed-rate renewal option for the period beyond the non-cancelable lease term, we evaluate factors such as the business conditions in the industry in which the lessee operates, the economic conditions in the area in which the property is located, and the ability of the lessee to sublease the property during the renewal term, in order to determine the likelihood that the lessee will renew.  When we determine there is reasonable assurance that such bargain purchase option will be exercised, we consider its impact in determining the intangible value of such lease and its related amortization period.  The value of tangible assets acquired is based upon our estimation of value on an “as if vacant” basis.  The value of acquired in-place leases includes the estimated costs during the hypothetical lease-up period and other costs that would have been incurred in the execution of similar leases, considering market conditions at the acquisition date of the acquired in-place lease.  We assess the fair value of tangible and intangible assets based on numerous factors, including estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information.  Estimates of future cash flows are based on a number of factors, including the historical operating results, known trends, and market/economic conditions that may affect the property.  We also recognize the fair values of assets acquired, the liabilities assumed, and any noncontrolling interest in acquisitions of less than a 100% interest when the acquisition constitutes a change in control of the acquired entity.  Costs related to the acquisition of businesses, including real estate acquired with in-place leases, are expensed as incurred.
	The values allocated to buildings and building improvements, land improvements, tenant improvements, and equipment are depreciated on a straight-line basis using the shorter of the term of the respective ground lease and up to 40 years for buildings and building improvements, an estimated life of 20 years for land improvements, the respective lease term for tenant improvements, and the estimated useful life for equipment. The values of acquired above and below market leases are amortized over the lives of the related leases and recognized as either an increase (for below market leases) or a decrease (for above market leases) to rental income. The values of acquired in-place leases are classified in other assets in the accompanying consolidated balance sheets, and amortized over the remaining terms of the related leases.
	We are required to capitalize project costs, including predevelopment costs, interest, property taxes, insurance, and other costs directly related and essential to the acquisition, development, redevelopment, predevelopment, or construction of a project.  Capitalization of development, redevelopment, predevelopment, and construction costs is required while activities are ongoing to prepare an asset for its intended use.  Fluctuations in our development, redevelopment, predevelopment, and construction activities could result in significant changes to total expenses and net income.  Costs incurred after a project is substantially complete and ready for its intended use are expensed as incurred.  Should development, redevelopment, predevelopment, or construction activities cease, interest, property taxes, insurance, and certain other costs would no longer be eligible for capitalization and would be expensed as incurred.  Expenditures for repairs and maintenance are expensed as incurred.
	A property is classified as “held for sale” when all of the following criteria for a plan of sale have been met: (i) management, having the authority to approve the action, commits to a plan to sell the property; (ii) the property is available for immediate sale in its present condition, subject only to terms that are usual and customary; (iii) an active program to locate a buyer and other actions required to complete the plan to sell have been initiated; (iv) the sale of the property is probable and is expected to be completed within one year; (v) the property is being actively marketed for sale at a price that is reasonable in relation to its current fair value; and (vi) actions necessary to complete the plan of sale indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn.  When all of these criteria have been met, the property is classified as “held for sale,” and if (i) the operations and cash flows of the property have been or will be eliminated from the ongoing operations, and (ii) we will not have any significant continuing involvement in the operations of the property after the sale, then its operations, including any interest expense directly attributable to it, are classified as discontinued operations in our consolidated statements of income, and amounts for all prior periods presented are reclassified from continuing operations to discontinued operations.  Depreciation of assets ceases upon designation of a property as “held for sale.”
	Impairment of long-lived assets
	Long-lived assets to be held and used, including our rental properties, land held for development, construction in progress, and intangibles, are individually evaluated for impairment when conditions exist that may indicate that the amount of a long-lived asset may not be recoverable.  The amount of a long-lived asset to be held and used is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset.  Impairment indicators or triggering events for long-lived assets to be held and used, including our rental properties, land held for development, and construction in progress, are assessed by project and include significant fluctuations in estimated net operating income (“NOI”), occupancy changes, significant near-term lease expirations, current and historical operating and/or cash flow losses, construction costs, estimated completion dates, rental rates, and other market factors.  We assess the expected undiscounted cash flows based upon numerous factors, including, but not limited to, construction costs, available market information, current and historical operating results, known trends, current market/economic conditions that may affect the property, and our assumptions about the use of the asset, including, if necessary, a probability-weighted approach if multiple outcomes are under consideration.  Upon determination that an impairment has occurred, a write-down is recognized to reduce the carrying amount to its estimated fair value.  If an impairment loss is not required to be recognized, the recognition of depreciation is adjusted prospectively, as necessary, to reduce the carrying amount of the real estate to its estimated disposition value over the remaining period that the real estate is expected to be held and used.  We may adjust depreciation of properties that are expected to be disposed of or redeveloped prior to the end of their useful lives.
	We use the “held for sale” impairment model for our properties classified as “held for sale.”  The “held for sale” impairment model is different from the held and used impairment model.  Under the “held for sale” impairment model, an impairment loss is recognized if the amount of the long-lived asset classified as “held for sale” exceeds its fair value less cost to sell.  Because of these two different models, it is possible for a long-lived asset previously classified as held and used to require the recognition of an impairment charge upon classification as “held for sale.”
	Investments
	We hold equity investments in certain publicly traded companies and investments in certain privately held entities primarily involved in the life science industry.  All of our investments in actively traded public companies are considered “available for sale” and are reflected in the accompanying consolidated balance sheets at fair value.  Fair value has been determined based upon the closing price as of each balance sheet date, with unrealized gains and losses shown as a separate component of comprehensive income.  The classification of each investment is determined at the time each investment is made, and such determination is reevaluated at each balance sheet date.  The cost of each investment sold is determined by the specific identification method, with realized gains or losses classified in other income in the accompanying consolidated statements of income.  Investments in privately held entities and limited partnerships are generally accounted for under the cost method when our interest in the entity is so minor that we have virtually no influence over the entity’s operating and financial policies.  Certain investments in privately held entities and limited partnerships are accounted for under the equity method when our interest in the entity is not deemed so minor that we have virtually no influence over the entity’s operating and financial policies.  Under the equity method of accounting, we recognize our investment initially at cost and adjust the amount of the investment to recognize our share of the earnings or losses of the investee subsequent to the date of our investment.  Additionally, we limit our ownership percentage in the voting interest of each individual entity to less than 10%.  As of June 30, 2014, and December 31, 2013, our ownership percentage in the voting interest of each individual entity was less than 10%.
	We monitor each of our investments throughout the year for new developments, including operating results, results of clinical trials, capital-raising events, and merger and acquisition activities. Individual investments are evaluated for impairment when changes in conditions may indicate an impairment exists.  The factors that we consider in making these assessments include, but are not limited to, market prices, market conditions, available financing, prospects for favorable or unfavorable clinical trial results, new product initiatives, and new collaborative agreements.  If there are no identified events or changes in circumstances that would have an adverse effect on our cost method investments, we do not estimate the investment’s fair value.  For all of our investments, if a decline in the fair value of an investment below the carrying value is determined to be other than temporary, such investment is written down to its estimated fair value with a charge to current earnings.
	Income taxes
	We are organized and qualify as a REIT pursuant to the Internal Revenue Code of 1986, as amended (the “Code”).  Under the Code, a REIT that distributes 100% of its REIT taxable income as a dividend to its shareholders each year and that meets certain other conditions is not subject to federal income taxes, but could be subject to certain state and local taxes.  We have distributed 100% or more of our taxable income.  Therefore, no provision for federal income taxes is required.  We file tax returns, including returns for our subsidiaries, with federal, state, and local jurisdictions, including jurisdictions located in the United States (“U.S.”), Canada, India, China, and other international locations.  Our tax returns are subject to examination in various jurisdictions for the calendar years 2009 through 2013.
	Recognition of rental income and tenant recoveries
	Rental income from leases is recognized on a straight-line basis over the respective lease terms.  We classify amounts currently recognized as income, and expected to be received in later years, as an asset in deferred rent in the accompanying consolidated balance sheets.  Amounts received currently, but recognized as income in future years, are classified in accounts payable, accrued expenses, and tenant security deposits in the accompanying consolidated balance sheets.  We commence recognition of rental income at the date the property is ready for its intended use and the client tenant takes possession of or controls the physical use of the property.
	Tenant recoveries related to reimbursement of real estate taxes, insurance, utilities, repairs and maintenance, and other operating expenses are recognized as revenue in the period during which the applicable expenses are incurred.
	Tenant receivables consist primarily of amounts due for contractual lease payments, reimbursements of common area maintenance expenses, property taxes, and other expenses recoverable from client tenants.  Tenant receivables are expected to be collected within one year.  We may maintain an allowance for estimated losses that may result from the inability of our client tenants to make payments required under the terms of the lease and for tenant recoveries due.  If a client tenant fails to make contractual payments beyond any allowance, we may recognize additional bad debt expense in future periods equal to the amount of uncollectible rent and deferred rent receivables arising from the straight-lining of rent.  As of June 30, 2014, and December 31, 2013, we had no allowance for estimated losses.
	Monitoring client tenant credit quality
	During the term of each lease, we monitor the credit quality of our client tenants by (i) reviewing the credit rating of tenants that are rated by a nationally recognized credit rating agency, (ii) reviewing financial statements of the client tenants that are publicly available or that are required to be delivered to us pursuant to the applicable lease, (iii) monitoring news reports regarding our client tenants and their respective businesses, and (iv) monitoring the timeliness of lease payments. We have a team of employees who, among them, have graduate and undergraduate degrees in biology, chemistry, and industrial biotechnology and experience in the life science industry, as well as in finance. This research team is responsible for assessing and monitoring the credit quality of our client tenants and any material changes in credit quality.
	Interest income
	Interest income was $911 thousand and $990 thousand during the three months ended June 30, 2014 and 2013, respectively. Interest income was $1.8 million and $2.3 million during the six months ended June 30, 2014 and 2013, respectively.  Interest income is included in other income in the accompanying consolidated statements of income.
	Impact of recently issued accounting standards
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update (“ASU”) on the reporting of discontinued operations, which raises the threshold for disposals to qualify as discontinued operations. Under this ASU, a discontinued operation is (i) a component of an entity or group of components that has been disposed of by sale, that has been disposed of other than by sale, or that is classified as “held for sale” and represents a strategic shift that has had or will have a major effect on an entity’s operations and financial results or (ii) an acquired business or nonprofit activity that is classified as “held for sale” on the date of the acquisition. A strategic shift that has or will have a major effect on an entity’s operations and financial results could include the disposal of (i) a major line of business, (ii) a major geographic area, (iii) a major equity method investment, or (iv) other major parts of an entity. Under current GAAP, an entity is prohibited from reporting a discontinued operation if it has certain continuing cash flows or involvement with the component after the disposal. This ASU eliminates these criteria and is effective for public companies during the interim and annual periods, beginning after December 15, 2014. We are required to adopt this ASU no later than January 1, 2015 and may early adopt this ASU during interim periods, as applicable. We expect the adoption of this ASU to result in fewer real estate sales qualifying for classification as discontinued operations in our consolidated financial statements.
	In May 2014, the FASB issued an ASU that replaces substantially all industry-specific revenue recognition requirements and converges areas under this topic with International Financial Reporting Standards. The ASU implements a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The ASU also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Other major provisions in this ASU include capitalizing and amortizing certain contract costs, ensuring the time value of money is considered in the applicable transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The ASU is effective for reporting periods beginning after December 15, 2016, and early adoption is prohibited. The ASU does not apply to lease contracts accounted for under current GAAP. We are currently evaluating the impact of the adoption of this ASU will have on our financial position and results of operations.

Investments_in_real_estate_net

Investments in real estate, net	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Investments in real estate, net	'
	Investments in real estate
	Our investments in real estate, consisted of the following as of June 30, 2014, and December 31, 2013 (in thousands):
		30-Jun-14			31-Dec-13
	Rental properties	$	6,668,458		$	6,442,208
	Less: accumulated depreciation	(1,039,810		)	(952,106		)
	Rental properties, net	5,628,648			5,490,102
	Construction in progress (“CIP”)/current value-creation projects:
	Current development in North America	613,104			558,482
	Current redevelopment in North America	32,139			8,856
	Current development in Asia	60,944			60,928
		706,187			628,266
		6,334,835			6,118,368
	Near-term value-creation projects in North America (CIP):
	50, 60, and 100 Binney Street	294,048			284,672
	Other projects	108,790			97,617
		402,838			382,289
	Future value-creation projects:
	North America	205,421			176,063
	Asia	79,328			77,251
		284,749			253,314
	Land subject to sale negotiations	7,695			22,943
	Investments in real estate	$	7,030,117		$	6,776,914
	Acquisitions
	In January 2014, we acquired 3545 Cray Court, a 116,556 RSF laboratory/office property located in the Torrey Pines submarket of San Diego, for $64.0 million. The property was 100% occupied on the date of acquisition. In connection with the acquisition, we assumed a $40.7 million non-recourse secured note payable with a contractual interest rate of 4.66% and a maturity in January 2023.
	In March 2014, we acquired 225 Second Avenue, a vacant 112,500 RSF office property located in the Route 128 submarket of Greater Boston, for $16.3 million. In May 2014, we leased 100% of the project to accommodate expansion requirements of an existing tenant. The property is undergoing conversion into laboratory/office space through redevelopment.
	In March 2014, we acquired 4025/4031/4045 Sorrento Valley Boulevard, three adjacent buildings aggregating 42,566 RSF located in the Sorrento Valley submarket of San Diego, for a total purchase price of $12.4 million. These properties were 100% occupied on the date of acquisition. In connection with the acquisition, we assumed a $7.6 million non-recourse secured note payable with a contractual interest rate of 5.74% and a maturity in April 2016.
	In April 2014, we acquired 500 Townsend Street, a land parcel supporting approximately 300,000 gross square feet, in the South of Market (“SoMa”) submarket of the San Francisco Bay Area for a purchase price of $50.0 million. We are in the process of perfecting entitlements, marketing for lease, and subject to market conditions, we plan to commence construction as soon as possible in 2015.
	Current development and redevelopment projects
	As of June 30, 2014, we had six ground-up development projects in process in North America aggregating 1.4 million RSF, including an unconsolidated joint venture development project. We also had three projects undergoing redevelopment in North America aggregating 197,289 RSF.
	Investment in unconsolidated real estate entity
	We are currently developing a building aggregating 413,536 RSF in the Longwood Medical Area of the Greater Boston market through an unconsolidated joint venture. The cost at completion for this unconsolidated joint venture is approximately $350.0 million. The project is 37% pre-leased to Dana-Farber Cancer Institute, Inc. The joint venture had a construction loan with commitments aggregating $213.2 million with $128.0 million outstanding as of June 30, 2014. The remaining cost to complete the development is expected to be funded primarily from the remaining commitments of $85.2 million under the construction loan. The construction loan bears interest at LIBOR+3.75%, with a floor of 5.25%, and has a maturity date of April 1, 2019, inclusive of two separate one-year options to extend the stated maturity date of April 1, 2017.
	We have a 27.5% interest in this unconsolidated joint venture that we account for under the equity method of accounting. Our investment under the equity method of accounting was $48.0 million as of June 30, 2014.
	We do not qualify as the primary beneficiary of the unconsolidated joint venture since we do not have the power to direct the activities of the entity that most significantly impact its economic performance. The decisions that most significantly impact the entity’s economic performance require both our consent and that of our partners, including all major operating, investing, and financing decisions, as well as decisions involving major expenditures. Consequently, we do not consolidate this joint venture, and we account for our investment under the equity method of accounting.
	Land undergoing predevelopment activities (CIP)
	Land undergoing predevelopment activities is classified as CIP and is undergoing activities prior to commencement of construction of aboveground building improvements.  We generally will not commence ground-up development of any parcels undergoing predevelopment activities without first securing pre-leasing for such space, except when there is significant market demand.  If aboveground construction is not initiated at completion of predevelopment activities, the land parcel will be classified as land held for development.  Our objective with predevelopment is to reduce the time it takes to deliver projects to prospective client tenants.  Additionally, during predevelopment, we focus on the design of cost-effective buildings with generic and reusable infrastructure to accommodate single and multi-tenancy. As of June 30, 2014, we held land undergoing predevelopment activities in North America aggregating 2.5 million RSF. The largest project included in land undergoing predevelopment activities consists of substantially all of our 1.1 million square feet at the Alexandria Center™ at Kendall Square located in East Cambridge, Massachusetts.
	Predevelopment costs generally include the following activities prior to commencement of vertical construction:
	Ÿ	Traditional predevelopment costs, including entitlement, design, construction drawings, BIM (3-D virtual modeling), budgeting, sustainability and energy optimization reviews, permitting, and planning for all aspects of the project; and
	Ÿ	Site and infrastructure construction costs, including belowground site work, utility connections, land grading, drainage, egress and regress access points, foundation, and other costs to prepare the site for construction of aboveground building improvements. For example, site and infrastructure costs for the 1.1 million RSF primarily related to 50, 60, and 100 Binney Street of the Alexandria Center™ at Kendall Square are classified as predevelopment prior to commencement of vertical construction.
	Land held for development
	Land held for development represents real estate we plan to develop in the future, but for which, as of each period presented, no construction or predevelopment activities were ongoing. As a result, interest, property taxes, insurance, and other costs are expensed as incurred. As of June 30, 2014, we had land held for development in North America supporting an aggregate of 3.2 million RSF of ground-up development.
	Dispositions
	During the six months ended June 30, 2014, we sold a land parcel for consideration of $19.0 million to a buyer expected to reposition the property for multi-family residential use. We recognized a gain of $0.8 million on the sale. This gain is classified in gain on sale of land parcel in the accompanying consolidated statements of income.

Investments

Investments	6 Months Ended
	Jun. 30, 2014
Investments [Abstract]	'
Investments	'
	Investments
	We hold investments in certain publicly traded companies and privately held entities, including limited partnerships, involved primarily in life science and related industries.  Our investments in publicly traded companies are accounted for as “available for sale” securities and are carried at their fair values.  Investments in “available for sale” securities with gross unrealized losses as of June 30, 2014, had been in a continuous unrealized loss position for less than 12 months. We have the ability and intent to hold these investments for a reasonable period of time sufficient for the recovery of our investment. We believe that these unrealized losses are temporary, and accordingly have not recognized other-than-temporary impairments related to “available for sale” securities as of June 30, 2014. As of June 30, 2014, and December 31, 2013, there were no unrealized losses in our investments in privately held entities, including limited partnerships.
	The following table summarizes our investments as of June 30, 2014, and December 31, 2013 (in thousands):
		30-Jun-14				31-Dec-13
	“Available-for-sale” marketable equity securities, cost basis	$	12,937			$	2,879
	Unrealized gains	19,338			(1)	2,177
	Unrealized losses	(1,297		)		(587		)
	“Available-for-sale” marketable equity securities, at fair value	30,978				4,469
	Investments accounted for under cost method	143,824				135,819
	Total investments	$	174,802			$	140,288
	-1	The increase in our investments during the six months ended June 30, 2014, was primarily related to an increase in unrealized gains of approximately $16.0 million related to our investments in publicly traded life science companies. These unrealized gains are a component of our comprehensive income, within our stockholders’ equity, and have not been recognized in the accompanying consolidated statement of income for the six months ended June 30, 2014.
	The following table outlines our investment (loss) income, which is classified in other income in the accompanying consolidated statements of income (in thousands):
		Three Months Ended June 30,							Six Months Ended June 30,
		2014				2013			2014			2013
	Investment gains	$	2,185			$	2,220		$	6,225		$	2,666
	Investment losses	(3,546		)		(143		)	(5,240		)	(529		)
	Investment (loss) income	$	(1,361	)		$	2,077		$	985		$	2,137

Secured_and_unsecured_senior_d

Secured and unsecured senior debt	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Secured and unsecured senior debt	'
	Secured and unsecured senior debt
	The following table summarizes our secured and unsecured senior debt as of June 30, 2014 (dollars in thousands):
		Fixed Rate/Hedged				Unhedged				Total				Weighted Average			Weighted Average
		Variable-Rate				Variable-Rate				Consolidated				Interest Rate at			Remaining Term
														End of Period (1)			(in years)
	Secured notes payable	$	415,655			$	199,896			$	615,551			4.83	%		3.2
	Unsecured senior notes payable	1,048,310				—				1,048,310				4.29			8.3
	$1.5 billion unsecured senior line of credit	—				571,000				571,000			(2)	1.25			4.5
	2016 Unsecured Senior Bank Term Loan	350,000				150,000				500,000			(2)	1.4			2.1
	2019 Unsecured Senior Bank Term Loan	600,000				—				600,000				2.05			4.5
	Total/weighted average	$	2,413,965			$	920,896			$	3,334,861			3.03	%		5.1
	Percentage of total debt	72		%		28		%		100		%
	-1	Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
	-2	These amounts do not reflect our unsecured senior notes payable offering completed on July 18, 2014. Net proceeds of $694 million were used to reduce variable-rate debt, including the partial repayment of $125 million of our 2016 Unsecured Senior Bank Term Loan and the reduction of $569 million of borrowings outstanding on our unsecured senior line of credit. See Note 13 – Subsequent Events, to our consolidated financial statements (unaudited) appearing elsewhere in this quarterly report on Form 10-Q for further information.
	The following table summarizes our outstanding consolidated indebtedness and respective principal maturities as of
	June 30, 2014 (dollars in thousands):
			Stated			Weighted Average			Maturity Date(2)		Principal Payments Remaining for the Period Ending December 31,
	Debt		Rate			Interest Rate(1)					2014				2015				2016				2017			2018			Thereafter			Total
	Secured notes payable
	San Diego		5.39	%		4	%		11/1/14		$	7,386			$	—			$	—			$	—		$	—		$	—		$	7,386
	Seattle		6			6			11/18/14		120				—				—				—			—			—			120
	Maryland		5.64			4.5			6/1/15		69				5,777				—				—			—			—			5,846
	San Francisco Bay Area		L+1.50			1.66			7/1/15		—				46,399				—				—			—			—			46,399
	Greater Boston, San Francisco Bay Area, and San Diego		5.73			5.73			1/1/16		862				1,816				75,501				—			—			—			78,179
	Greater Boston, San Diego, and New York City		5.82			5.82			4/1/16		465				988				29,389				—			—			—			30,842
	San Diego		5.74			3			4/15/16		83				175				6,916				—			—			—			7,174
	San Francisco Bay Area		L+1.40			1.56			6/1/16		—				—				11,936				—			—			—			11,936
	San Francisco Bay Area		6.35			6.35			8/1/16		1,229				2,652				126,715				—			—			—			130,596
	Maryland		2.14			2.14			1/20/17		—				—				—				76,000			—			—			76,000
	Greater Boston		L+1.35			1.5			8/23/17		—				—				—				65,440			—			—			65,440
	San Diego, Maryland, and Seattle		7.75			7.75			4/1/20		741				1,570				1,696				1,832			1,979			106,490			114,308
	San Diego		4.66			4.66			1/1/23		669				1,402				1,464				1,540			1,614			33,367			40,056
	San Francisco Bay Area		6.5			6.5			6/1/37		—				18				19				20			22			751			830
	Unamortized premiums										161				218				60				—			—			—			439
	Secured notes payable average/subtotal		4.89	%		4.83					11,785				61,015				253,696				144,832			3,615			140,608			615,551
	2016 Unsecured Senior Bank Term Loan		L+1.20	%		1.4			7/31/16		—				—				500,000				—			—			—			500,000
	2019 Unsecured Senior Bank Term Loan		L+1.20	%		2.05			1/3/19		—				—				—				—			—			600,000			600,000
	$1.5 billion unsecured senior line of credit		L+1.10	%	(3)	1.25			1/3/19		—				—				—				—			—			571,000			571,000
	Unsecured senior notes payable		4.6	%		4.61			4/1/22		—				—				—				—			—			550,000			550,000
	Unsecured senior notes payable		3.9	%		3.94			6/15/23		—				—				—				—			—			500,000			500,000
	Unamortized discounts										(82		)		(170		)		(177		)		(184		)	(192		)	(885		)	(1,690		)
	Unsecured debt average/subtotal					2.63					(82		)		(170		)		499,823				(184		)	(192		)	2,220,115			2,719,310
	Average/total					3.03	%				$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	Balloon payments										$	7,339			$	52,139			$	748,836			$	141,440		$	—		$	2,351,238		$	3,300,992
	Principal amortization										4,364				8,706				4,683				3,208			3,423			9,485			33,869
	Total consolidated debt										$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	Fixed-rate/hedged variable-rate debt										$	11,583			$	14,446			$	591,582			$	3,208		$	3,423		$	1,789,723		$	2,413,965
	Unhedged variable-rate debt										120				46,399				161,937				141,440			—			571,000			920,896
	Total consolidated debt										$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	-1	Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
	-2	Includes any extension options that we control.
	-3	In addition to the stated rate, the unsecured senior line of credit is subject to an annual facility fee of 0.20%.
	Interest expense
	The following table summarizes interest expense for the three and six months ended June 30, 2014 and 2013 (in thousands):
		Three Months Ended June 30,								Six Months Ended June 30,
		2014				2013				2014				2013
	Gross interest	$	28,735			$	31,668			$	59,871			$	63,709
	Capitalized interest	(11,302		)		(15,690		)		(23,315		)		(29,711		)
	Interest expense	$	17,433			$	15,978			$	36,556			$	33,998
	Repayment of secured note payable
	In January 2014, we repaid our $208.7 million secured note payable related to Alexandria Technology Square®. Our joint venture partner funded $20.9 million of the proceeds required to repay the secured note payable.
	Secured construction loans
	The following table summarizes our secured construction loans as of June 30, 2014 (dollars in thousands):
Address		Market		Stated Rate				Maturity Date				Outstanding Balance				Remaining Commitments				Total Aggregate Commitments
259 East Grand Avenue		San Francisco Bay Area			L+1.50	%		7/1/15		(1)		$	46,399			$	8,601			$	55,000
269 East Grand Avenue		San Francisco Bay Area			L+1.40	%		6/1/16		(2)		11,936				24,064				36,000
75/125 Binney Street		Greater Boston			L+1.35	%		8/23/17		(3)		65,440				184,960				250,400
												$	123,775			$	217,625			$	341,400
-1	We have two, one-year options to extend the stated maturity date to July 1, 2017, subject to certain conditions.
-2	We have two, one-year options to extend the stated maturity date to June 1, 2018, subject to certain conditions.
-3	We have a one-year option to extend the stated maturity date to August 23, 2018, subject to certain conditions.

Interest_rate_swap_agreements

Interest rate swap agreements	6 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Interest rate swap agreements	'
	Interest rate swap agreements
	We use interest rate swap agreements to hedge the variable cash flows associated with certain of our existing LIBOR-based variable-rate debt, including our unsecured senior line of credit and unsecured senior bank term loans.  The ineffective portion of the change in fair value of our interest rate swap agreements is required to be recognized directly in earnings.  During the six months ended June 30, 2014 and 2013, our interest rate swap agreements were 100% effective; because of this, no hedge ineffectiveness was recognized in earnings.  Changes in fair value, including accrued interest and adjustments for non-performance risk, on the effective portion of our interest rate swap agreements that are designated and that qualify as cash flow hedges are classified in accumulated other comprehensive loss. Amounts classified in accumulated other comprehensive loss are subsequently reclassified into earnings in the period during which the hedged transactions affect earnings.  During the next 12 months, we expect to reclassify approximately $3.1 million in accumulated other comprehensive loss to interest expense as an increase to interest expense. As of June 30, 2014, and December 31, 2013, the fair values of our interest rate swap agreements aggregating an asset balance were classified in other assets, and those aggregating a liability balance were classified in accounts payable, accrued expenses, and tenant security deposits, based upon their respective fair values. Under our interest rate swap agreements, we have no collateral posting requirements.
	As of June 30, 2014, the fair value of derivatives in a net liability position was $2.6 million. The Company has agreements with certain of its derivative counterparties that contain a provision wherein (i) the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness; or (ii) if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. If the Company had breached any of these provisions at June 30, 2014, it could have been required to settle its obligations under the agreements at their termination value of $2.6 million.
	We had the following outstanding interest rate swap agreements that were designated as cash flow hedges of interest rate risk as of June 30, 2014 (dollars in thousands):
	Effective Date		Maturity Date	Number of Contracts	Weighted Average Interest Pay	Fair Value as of 6/30/14			Notional Amount in Effect as of
					Rate (1)				6/30/14		12/31/14		12/31/15		12/31/16
	31-Dec-13		31-Dec-14	2	0.98%	$	(2,114	)	$	500,000	$	—	$	—	$	—
	31-Dec-13		31-Mar-15	2	0.23%	(144		)	250,000		250,000		—		—
	31-Mar-14		31-Mar-15	4	0.21%	(75		)	200,000		200,000		—		—
	31-Dec-14		31-Mar-16	3	0.53%	(335		)	—		500,000		500,000		—
	31-Mar-16		31-Mar-17	3	1.40%	46			—		—		—		500,000
	Total					$	(2,622	)	$	950,000	$	950,000	$	500,000	$	500,000
	-1	In addition to the interest pay rate, borrowings outstanding as of June 30, 2014, under our unsecured senior bank term loans include an applicable margin of 1.20% and borrowings outstanding under our unsecured senior line of credit include an applicable margin of 1.10%.

Fair_value_measurements

Fair value measurements	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair value measurements	'
	Fair value measurements
	We are required to disclose fair value information about all financial instruments, whether or not recognized in the balance sheet, for which it is practicable to estimate fair value.  We measure and disclose the estimated fair value of financial assets and liabilities utilizing a fair value hierarchy that distinguishes between data obtained from sources independent of the reporting entity and the reporting entity’s own assumptions about market participant assumptions.  This hierarchy consists of three broad levels, as follows: (i) quoted prices in active markets for identical assets or liabilities, (ii) “significant other observable inputs,” and (iii) “significant unobservable inputs.”  “Significant other observable inputs” can include quoted prices for similar assets or liabilities in active markets, as well as inputs that are observable for the asset or liability, such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals.  “Significant unobservable inputs” are typically based on an entity’s own assumptions, since there is little, if any, related market activity.  In instances in which the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level of input that is significant to the fair value measurement in its entirety.  Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.  There were no transfers between the levels in the fair value hierarchy during the three and six months ended June 30, 2014 and 2013.
	The following tables set forth the assets and liabilities that we measure at fair value on a recurring basis by level within the fair value hierarchy as of June 30, 2014, and December 31, 2013 (in thousands):
						30-Jun-14
	Description		Total			Quoted Prices in			Significant			Significant
						Active Markets			Other			Unobservable
						for Identical			Observable			Inputs
						Assets			Inputs
	Assets:
	“Available-for-sale” securities		$	30,978		$	30,978		$	—		$	—
	Interest rate swap agreements		$	46		$	—		$	46		$	—
	Liabilities:
	Interest rate swap agreements		$	2,668		$	—		$	2,668		$	—
						31-Dec-13
	Description		Total			Quoted Prices in			Significant			Significant
						Active Markets			Other			Unobservable
						for Identical			Observable			Inputs
						Assets			Inputs
	Assets:
	“Available-for-sale” securities		$	4,469		$	4,469		$	—		$	—
	Interest rate swap agreements		$	2,870		$	—		$	2,870		$	—
	Liabilities:
	Interest rate swap agreements		$	6,191		$	—		$	6,191		$	—
	Cash and cash equivalents, restricted cash, tenant receivables, other assets, accounts payable, accrued expenses, and tenant security deposits approximate fair value.  Our “available-for-sale” securities and our interest rate swap agreements, respectively, have been recognized at fair value.  See Note 6 – Interest Rate Swap Agreements for further details on our interest rate swap agreements. The fair values of our secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loans were estimated using widely accepted valuation techniques, including discounted cash flow analyses of “significant other observable inputs” such as available market information on discount and borrowing rates with similar terms, maturities, and credit ratings.  Because the valuations of our financial instruments are based on these types of estimates, the actual fair value of our financial instruments may differ materially if our estimates do not prove to be accurate.  Additionally, the use of different market assumptions or estimation methods may have a material effect on the estimated fair value amounts.
	As of June 30, 2014, and December 31, 2013, the book and fair values of our “available-for-sale” marketable equity securities, interest rate swap agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loans were as follows (in thousands):
		30-Jun-14						31-Dec-13
		Book Value			Fair Value			Book Value			Fair Value
	Assets:
	“Available-for-sale” marketable equity securities	$	30,978		$	30,978		$	4,469		$	4,469
	Interest rate swap agreements	$	46		$	46		$	2,870		$	2,870
	Liabilities:
	Interest rate swap agreements	$	2,668		$	2,668		$	6,191		$	6,191
	Secured notes payable	$	615,551		$	664,724		$	708,831		$	736,772
	Unsecured senior notes payable	$	1,048,310		$	1,081,305		$	1,048,230		$	1,043,125
	Unsecured senior line of credit	$	571,000		$	570,393		$	204,000		$	193,714
	Unsecured senior bank term loans	$	1,100,000		$	1,099,326		$	1,100,000		$	1,099,897

Earnings_per_share

Earnings per share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Earnings per share	'
	Earnings per share
	We use income from continuing operations attributable to Alexandria’s common stockholders as the “control number” in determining whether potential common shares are dilutive or antidilutive to earnings per share.  Pursuant to the presentation and disclosure literature on gains or losses on sales or disposals by REITs and earnings per share required by the SEC and the FASB, gains or losses on sales or disposals by a REIT that do not qualify as discontinued operations are classified below income from discontinued operations in the consolidated statements of income and included in the numerator for the computation of earnings per share for income from continuing operations.
	The land parcels we sold during the three and six months ended June 30, 2014 and 2013, did not meet the criteria for classification as discontinued operations because the land parcels did not have significant operations prior to disposition.  Accordingly, for the three and six months ended June 30, 2014 and 2013, we classified approximately $797 thousand and $772 thousand, respectively, as gain on sale of land parcel below income from discontinued operations, net, in the accompanying consolidated statements of income, and included the gain in income from continuing operations attributable to Alexandria’s common stockholders in the “control number,” or numerator, for computation of earnings per share.
	We account for unvested restricted stock awards that contain nonforfeitable rights to dividends as participating securities and include these securities in the computation of earnings per share using the two-class method.  Our Series D cumulative convertible preferred stock (“Series D Preferred Stock”) is not a participating security, and is not included in the computation of earnings per share using the two-class method.  Under the two-class method, we allocate net income after preferred stock dividends, preferred stock redemption charge, and amounts attributable to noncontrolling interests to common stockholders and unvested restricted stock awards based on their respective participation rights to dividends declared (or accumulated) and undistributed earnings.  Diluted earnings per share is computed using the weighted average shares of common stock outstanding determined for the basic earnings per share computation plus the effect of any dilutive securities, including the dilutive effect of stock options using the treasury stock method, during the period the securities were outstanding.
	The table below is a reconciliation of the numerators and denominators of the basic and diluted earnings per share computations for the three and six months ended June 30, 2014 and 2013 (dollars in thousands, except per share amounts):
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Income from continuing operations	$	35,466		$	32,316		$	76,377		$	61,716
	Gain on sale of land parcel	797			772			797			772
	Dividends on preferred stock	(6,472		)	(6,471		)	(12,943		)	(12,942		)
	Net income attributable to noncontrolling interests	(1,307		)	(980		)	(2,502		)	(1,962		)
	Net income attributable to unvested restricted stock awards	(405		)	(403		)	(779		)	(745		)
	Income from continuing operations attributable to Alexandria’s common stockholders – basic and diluted	28,079			25,234			60,950			46,839
	(Loss) income from discontinued operations	(147		)	249			(309		)	1,086
	Net income attributable to Alexandria’s common stockholders – basic and diluted	$	27,932		$	25,483		$	60,641		$	47,925
	Weighted average shares of common stock outstanding – basic and diluted	71,126			66,973			71,100			65,078
	Earnings per share attributable to Alexandria’s common stockholders – basic and diluted:
	Continuing operations	$	0.39		$	0.38		$	0.85		$	0.72
	Discontinued operations	—			—			—			0.02
	Earnings per share – basic and diluted	$	0.39		$	0.38		$	0.85		$	0.74
	For purposes of calculating diluted earnings per share, we did not assume conversion of our Series D Preferred Stock for the three and six months ended June 30, 2014 and 2013, since the impact was antidilutive to earnings per share attributable to Alexandria’s common stockholders from continuing operations during those periods.

Net_income_attributable_to_Ale

Net income attributable to Alexandria Real Estate Equities, Inc.	6 Months Ended
	Jun. 30, 2014
Net Income (Loss) Attributable to Parent [Abstract]	'
Net income attributable to Alexandria Real Estate Equities, Inc.	'
	Net income attributable to Alexandria Real Estate Equities, Inc.
	The following table presents income from continuing and discontinued operations attributable to Alexandria Real Estate Equities, Inc. for the three and six months ended June 30, 2014 and 2013 (in thousands):
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Income from continuing operations	$	35,466		$	32,316		$	76,377		$	61,716
	Gain on sale of land parcel	797			772			797			772
	Less: net income attributable to noncontrolling interests	(1,307		)	(980		)	(2,502		)	(1,962		)
	Income from continuing operations attributable to Alexandria Real Estate Equities, Inc.	34,956			32,108			74,672			60,526
	(Loss) income from discontinued operations	(147		)	249			(309		)	1,086
	Net income attributable to Alexandria Real Estate Equities, Inc.	$	34,809		$	32,357		$	74,363		$	61,612

Stockholders_equity

Stockholders' equity	6 Months Ended
	Jun. 30, 2014
Stockholders' Equity Note [Abstract]	'
Stockholders' equity	'
	Dividends
	In June 2014, we declared cash dividends on our common stock for the second quarter of 2014, aggregating $51.7 million, or $0.72 per share.  In June 2014, we also declared cash dividends on our Series D Preferred Stock for the second quarter of 2014, aggregating approximately $4.4 million, or $0.4375 per share.  Additionally, we declared cash dividends on our Series E cumulative redeemable preferred stock (“Series E Preferred Stock”) for the second quarter of 2014, aggregating approximately $2.1 million, or $0.403125 per share.  In July 2014, we paid the cash dividends on our common stock, Series D Preferred Stock, and Series E Preferred Stock for the second quarter of 2014.
	Accumulated other comprehensive loss
	Accumulated other comprehensive loss attributable to Alexandria Real Estate Equities, Inc. consists of the following (in thousands):
		Unrealized Gain on Marketable Securities		Unrealized Loss on Interest Rate			Unrealized Loss on Foreign Currency Translation			Total
				Swap Agreements
	Balance as of December 31, 2013	$	1,590	$	(3,321	)	$	(34,473	)	$	(36,204	)
	Other comprehensive income before reclassifications	16,045		(3,914		)	2,809			14,940
	Amounts reclassified from other comprehensive income	406		4,613			—			5,019
	Net other comprehensive income	16,451		699			2,809			19,959
	Balance as of June 30, 2014	$	18,041	$	(2,622	)	$	(31,664	)	$	(16,245	)
	Preferred stock and excess stock authorizations
	Our charter authorizes the issuance of up to 100.0 million shares of preferred stock, of which 15.2 million shares were issued and outstanding as of June 30, 2014.  In addition, 200.0 million shares of “excess stock” (as defined in our charter) are authorized, none of which were issued and outstanding as of June 30, 2014.

Noncontrolling_interests

Noncontrolling interests	6 Months Ended
	Jun. 30, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling interests	'
	Noncontrolling interests
	Noncontrolling interests represent the third-party interests in certain entities in which we have a controlling interest.  These entities owned 10 properties and three development parcels as of June 30, 2014, and are included in our consolidated financial statements.  Noncontrolling interests are adjusted for additional contributions and distributions, the proportionate share of the net earnings or losses, and other comprehensive income or loss.  Distributions, profits, and losses related to these entities are allocated in accordance with the respective operating agreements.
	Certain of our noncontrolling interests have the right to require us to redeem their ownership interests in the respective entities.  We classify these ownership interests in the entities as redeemable noncontrolling interests outside of total equity in the accompanying consolidated balance sheets.  Redeemable noncontrolling interests are adjusted for additional contributions and distributions, the proportionate share of the net earnings or losses, and other comprehensive income or loss.  Distributions, profits, and losses related to these entities are allocated in accordance with the respective operating agreements.  If the amount of a redeemable noncontrolling interest is less than the maximum redemption value at the balance sheet date, such amount is adjusted to the maximum redemption value.  Subsequent declines in the redemption value are recognized only to the extent that previous increases have been recognized.  As of June 30, 2014, and December 31, 2013, our redeemable noncontrolling interest balances were $14.4 million and $14.4 million, respectively.  Our remaining noncontrolling interests, aggregating $67.7 million and $47.7 million as of June 30, 2014, and December 31, 2013, respectively, do not have rights to require us to purchase their ownership interests and are classified in total equity in the accompanying consolidated balance sheets.

Discontinued_operations

Discontinued operations	6 Months Ended
	Jun. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued operations	'
	Discontinued operations
	The following is a summary of net assets of discontinued operations and (loss) income from discontinued operations (in thousands):
		June 30, 2014				December 31, 2013
	Properties “held for sale,” net	$	7,651			$	7,644
	Other assets	35				103
	Total assets	7,686				7,747
	Total liabilities	(135		)		(266		)
	Net assets of discontinued operations	$	7,551			$	7,481
			Three Months Ended June 30,							Six Months Ended June 30,
			2014				2013			2014			2013
	Total revenues		$	—			$	546		$	—		$	4,339
	Operating expenses		147				280			309			1,730
	Total revenues less operating expenses from discontinued operations		(147		)		266			(309		)	2,609
	Depreciation expense		—				236			—			1,402
	(Gain) loss on sale of real estate		—				(219		)	—			121
	(Loss) income from discontinued operations (1)		$	(147	)		$	249		$	(309	)	$	1,086
	-1	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Subsequent_events

Subsequent events	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent events	'
	Subsequent events
	$700 million offering of unsecured senior notes payable
	In July 2014, we completed an offering of $700 million aggregate principal amount of unsecured senior notes payable at an average interest rate of 3.5% and an average maturity of 9.6 years, consisting of $400 million of our 2.75% unsecured senior notes payable due in 2020 (“2.75% Unsecured Senior Notes”) and $300 million aggregate principal amount of our 4.50% unsecured senior notes payable due in 2029 (“4.50% Unsecured Senior Notes”). Net proceeds of $694 million were used to repay $125 million of our 2016 unsecured senior bank term loan (“2016 Unsecured Senior Bank Term Loan”) and $569 million of the amounts outstanding on our unsecured senior line of credit. In connection with the partial repayment of $125 million of our 2016 Unsecured Senior Bank Term Loan, we recognized a loss on the early extinguishment of debt related to the write-off of unamortized loan fees totaling $0.5 million.
	Dispositions
	In July 2014, we completed the sale of two land parcels in a non-cluster market for a sales price of $7.9 million and a gain of $207 thousand.

Condensed_consolidating_financ

Condensed consolidating financial information	6 Months Ended
	Jun. 30, 2014
Condensed Consolidated Financial Information [Abstract]	'
Condensed consolidating financial information	'
	Condensed consolidating financial information
	Alexandria Real Estate Equities, Inc. (the “Issuer”) has sold certain debt securities registered under the Securities Act, as amended, that are fully and unconditionally guaranteed by Alexandria Real Estate Equities, L.P. (the “LP” or the “Guarantor Subsidiary”), an indirectly 100% owned subsidiary of the Issuer. The Company’s other subsidiaries, including, but not limited to, the subsidiaries that own substantially all of its real estate (collectively, the “Combined Non-Guarantor Subsidiaries”) will not provide a guarantee of such securities, including the subsidiaries that are partially or 100% owned by the LP. The following condensed consolidating financial information presents the condensed consolidating balance sheets as of June 30, 2014, and December 31, 2013, and the condensed consolidating statements of income and comprehensive income for the three and six months ended June 30, 2014 and 2013, and condensed consolidating cash flows for the six months ended June 30, 2014 and 2013, for the Issuer, the Guarantor Subsidiary, the Combined Non-Guarantor Subsidiaries, the eliminations necessary to arrive at the information for Alexandria Real Estate Equities, Inc. on a consolidated basis, and consolidated amounts. In presenting the condensed consolidating financial statements, the equity method of accounting has been applied to (i) the Issuer’s interests in the Guarantor Subsidiary and the Combined Non-Guarantor Subsidiaries, (ii) the Guarantor Subsidiary’s interests in the Combined Non-Guarantor Subsidiaries, and (iii) the Combined Non-Guarantor Subsidiaries’ interests in the Guarantor Subsidiary, where applicable, even though all such subsidiaries meet the requirements to be consolidated under GAAP. All intercompany balances and transactions between the Issuer, the Guarantor Subsidiary, and the Combined Non-Guarantor Subsidiaries have been eliminated, as shown in the column “Eliminations.” All assets and liabilities have been allocated to the Issuer, the Guarantor Subsidiary, and the Combined Non-Guarantor Subsidiaries generally based on legal entity ownership.
	Condensed Consolidating Balance Sheet
	as of June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria Real Estate Equities, Inc.			Alexandria			Combined			Eliminations			Consolidated
		(Issuer)			Real Estate			Non-
					Equities, L.P.			Guarantor
					(Guarantor			Subsidiaries
					Subsidiary)
	Assets
	Investments in real estate	$	—		$	—		$	7,030,117		$	—		$	7,030,117
	Cash and cash equivalents	18,041			—			43,660			—			61,701
	Restricted cash	64			—			24,455			—			24,519
	Tenant receivables	—			—			10,654			—			10,654
	Deferred rent	—			—			214,793			—			214,793
	Deferred leasing and financing costs	33,298			—			160,323			—			193,621
	Investments	—			9,637			165,165			—			174,802
	Investments in and advances to affiliates	6,678,756			6,162,162			125,591			(12,966,509		)	—
	Other assets	18,740			—			86,702			—			105,442
	Total assets	$	6,748,899		$	6,171,799		$	7,861,460		$	(12,966,509	)	$	7,815,649
	Liabilities, Noncontrolling Interests, and Equity
	Secured notes payable	$	—		$	—		$	615,551		$	—		$	615,551
	Unsecured senior notes payable	1,048,310			—			—			—			1,048,310
	Unsecured senior line of credit	571,000			—			—			—			571,000
	Unsecured senior bank term loans	1,100,000			—			—			—			1,100,000
	Accounts payable, accrued expenses, and tenant security deposits	65,700			—			368,828			—			434,528
	Dividends payable	57,087			—			290			—			57,377
	Total liabilities	2,842,097			—			984,669			—			3,826,766
	Redeemable noncontrolling interests	—			—			14,381			—			14,381
	Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,906,802			6,171,799			6,794,710			(12,966,509		)	3,906,802
	Noncontrolling interests	—			—			67,700			—			67,700
	Total equity	3,906,802			6,171,799			6,862,410			(12,966,509		)	3,974,502
	Total liabilities, noncontrolling interests, and equity	$	6,748,899		$	6,171,799		$	7,861,460		$	(12,966,509	)	$	7,815,649
	Condensed Consolidating Balance Sheet
	as of December 31, 2013
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Assets
	Investments in real estate	$	—		$	—		$	6,776,914		$	—		$	6,776,914
	Cash and cash equivalents	14,790			—			42,906			—			57,696
	Restricted cash	55			—			27,654			—			27,709
	Tenant receivables	—			—			9,918			—			9,918
	Deferred rent	—			—			190,425			—			190,425
	Deferred leasing and financing costs	36,901			—			155,757			—			192,658
	Investments	—			10,868			129,420			—			140,288
	Investments in and advances to affiliates	6,299,551			5,823,058			119,421			(12,242,030		)	—
	Other assets	20,226			—			113,930			—			134,156
	Total assets	$	6,371,523		$	5,833,926		$	7,566,345		$	(12,242,030	)	$	7,529,764
	Liabilities, Noncontrolling Interests, and Equity
	Secured notes payable	$	—		$	—		$	708,831		$	—		$	708,831
	Unsecured senior notes payable	1,048,230			—			—			—			1,048,230
	Unsecured senior line of credit	204,000			—			—			—			204,000
	Unsecured senior bank term loans	1,100,000			—			—			—			1,100,000
	Accounts payable, accrued expenses, and tenant security deposits	48,373			—			386,969			—			435,342
	Dividends payable	54,131			—			289			—			54,420
	Total liabilities	2,454,734			—			1,096,089			—			3,550,823
Redeemable noncontrolling interests	—			—			14,444			—			14,444
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,916,789			5,833,926			6,408,104			(12,242,030		)	3,916,789
Noncontrolling interests	—			—			47,708			—			47,708
Total equity	3,916,789			5,833,926			6,455,812			(12,242,030		)	3,964,497
Total liabilities, noncontrolling interests, and equity	$	6,371,523		$	5,833,926		$	7,566,345		$	(12,242,030	)	$	7,529,764
Condensed Consolidating Statement of Income
for the Three Months Ended June 30, 2014
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Revenues:
Rental	$	—		$	—		$	134,992		$	—		$	134,992
Tenant recoveries	—			—			40,944			—			40,944
Other income	2,916			(1,535		)	2,532			(3,447		)	466
Total revenues	2,916			(1,535		)	178,468			(3,447		)	176,402
Expenses:
Rental operations	—			—			52,353			—			52,353
General and administrative	11,506			—			5,777			(3,447		)	13,836
Interest	12,493			—			4,940			—			17,433
Depreciation and amortization	1,456			—			55,858			—			57,314
Total expenses	25,455			—			118,928			(3,447		)	140,936
(Loss) income from continuing operations before equity in earnings of affiliates	(22,539		)	(1,535		)	59,540			—			35,466
Equity in earnings of affiliates	57,355			56,302			1,081			(114,738		)	—
Income from continuing operations	34,816			54,767			60,621			(114,738		)	35,466
Loss from discontinued operations	(7		)	—			(140		)	—			(147		)
Gain on sale of land parcel	—			—			797			—			797
Net income	34,809			54,767			61,278			(114,738		)	36,116
Dividends on preferred stock	(6,472		)	—			—			—			(6,472		)
Net income attributable to noncontrolling interests	—			—			(1,307		)	—			(1,307		)
Net income attributable to unvested restricted stock awards	(405		)	—			—			—			(405		)
Net income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	27,932		$	54,767		$	59,971		$	(114,738	)	$	27,932
Condensed Consolidating Statement of Income
for the Three Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Revenues:
Rental	$	—		$	—		$	114,493		$	—		$	114,493
Tenant recoveries	—			—			35,869			—			35,869
Other income	2,674			(75		)	4,098			(3,129		)	3,568
Total revenues	2,674			(75		)	154,460			(3,129		)	153,930
Expenses:
Rental operations	—			—			46,277			—			46,277
General and administrative	12,164			—			3,420			(3,129		)	12,455
Interest	10,090			—			5,888			—			15,978
Depreciation and amortization	1,446			—			44,898			—			46,344
Loss on early extinguishment of debt	560			—			—			—			560
Total expenses	24,260			—			100,483			(3,129		)	121,614
(Loss) income from continuing operations before equity in earnings of affiliates	(21,586		)	(75		)	53,977			—			32,316
Equity in earnings of affiliates	53,912			48,944			939			(103,795		)	—
Income from continuing operations	32,326			48,869			54,916			(103,795		)	32,316
Income from discontinued operations	31			—			218			—			249
Gain on sale of land parcel	—			—			772			—			772
Net income	32,357			48,869			55,906			(103,795		)	33,337
Dividends on preferred stock	(6,471		)	—			—			—			(6,471		)
Net income attributable to noncontrolling interests	—			—			(980		)	—			(980		)
Net income attributable to unvested restricted stock awards	(403		)	—			—			—			(403		)
Net income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	25,483		$	48,869		$	54,926		$	(103,795	)	$	25,483
Condensed Consolidating Statement of Comprehensive Income
for the Three Months Ended June 30, 2014
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Net income	$	34,809		$	54,767		$	61,278		$	(114,738	)	$	36,116
Other comprehensive income:
Unrealized gains (losses) on marketable securities:
Unrealized holding gains (losses) arising during the period	—			310			(3,044		)	—			(2,734		)
Reclassification adjustment for losses included in net income	—			—			406			—			406
Unrealized gains (losses) on marketable securities, net	—			310			(2,638		)	—			(2,328		)
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap losses arising during the period	(2,526		)	—			—			—			(2,526		)
Reclassification adjustment for amortization of interest expense included in net income	1,123			—			—			—			1,123
Unrealized losses on interest rate swap agreements	(1,403		)	—			—			—			(1,403		)
Foreign currency translation gains	—			—			5,915			—			5,915
Total other comprehensive (loss) income	(1,403		)	310			3,277			—			2,184
Comprehensive income	33,406			55,077			64,555			(114,738		)	38,300
Less: comprehensive income attributable to noncontrolling interests	—			—			(1,307		)	—			(1,307		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	33,406		$	55,077		$	63,248		$	(114,738	)	$	36,993
Condensed Consolidating Statement of Comprehensive Income
for the Three Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Net income	$	32,357		$	48,869		$	55,906		$	(103,795	)	$	33,337
Other comprehensive income:
Unrealized (losses) gains on marketable securities:
Unrealized holding (losses) gains arising during the period	—			(244		)	288			—			44
Reclassification adjustment for losses (gains) included in net income	—			106			(64		)	—			42
Unrealized (losses) gains on marketable securities	—			(138		)	224			—			86
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap losses arising during the period	105			—			—			—			105
Reclassification adjustment for amortization of interest expense included in net income	3,834			—			—			—			3,834
Unrealized gains on interest rate swap agreements	3,939			—			—			—			3,939
Foreign currency translation losses	—			—			(20,698		)	—			(20,698		)
Total other comprehensive income (loss)	3,939			(138		)	(20,474		)	—			(16,673		)
Comprehensive income	36,296			48,731			35,432			(103,795		)	16,664
Less: comprehensive income attributable to noncontrolling interests	—			—			(1,008		)	—			(1,008		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	36,296		$	48,731		$	34,424		$	(103,795	)	$	15,656
Condensed Consolidating Statement of Comprehensive Income
for the Six Months Ended June 30, 2014
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Net income	$	74,363		$	113,073		$	126,126		$	(236,697	)	$	76,865
Other comprehensive income:
Unrealized gains on marketable securities:
Unrealized holding gains arising during the period	—			310			15,735			—			16,045
Reclassification adjustment for losses included in net income	—			—			406			—			406
Unrealized gains on marketable securities	—			310			16,141			—			16,451
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap gains arising during the period	(3,914		)	—			—			—			(3,914		)
Reclassification adjustment for amortization of interest expense included in net income	4,613			—			—			—			4,613
Unrealized gains on interest rate swap agreements	699			—			—			—			699
Foreign currency translation gains	—			—			2,809			—			2,809
Total other comprehensive income	699			310			18,950			—			19,959
Comprehensive income	75,062			113,383			145,076			(236,697		)	96,824
Less: comprehensive income attributable to noncontrolling interests	—			—			(2,502		)	—			(2,502		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	75,062		$	113,383		$	142,574		$	(236,697	)	$	94,322
Condensed Consolidating Statement of Comprehensive Income
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Net income	$	61,612		$	96,042		$	107,721		$	(201,801	)	$	63,574
Other comprehensive income:
Unrealized gains on marketable securities:
Unrealized holding gains (losses) arising during the period	—			405			(45		)	—			360
Reclassification adjustment for (gains) losses included in net income	—			(375		)	145			—			(230		)
Unrealized gains on marketable securities	—			30			100			—			130
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap losses arising during the period	(28		)	—			—			—			(28		)
Reclassification adjustment for amortization of interest expense included in net income	8,142			—			—			—			8,142
Unrealized gains on interest rate swap agreements	8,114			—			—			—			8,114
Foreign currency translation losses	—			—			(23,057		)	—			(23,057		)
Total other comprehensive income (loss)	8,114			30			(22,957		)	—			(14,813		)
Comprehensive income	69,726			96,072			84,764			(201,801		)	48,761
Less: comprehensive income attributable to noncontrolling interests	—			—			(1,906		)	—			(1,906		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	69,726		$	96,072		$	82,858		$	(201,801	)	$	46,855
Condensed Consolidating Statement of Cash Flows
for the Six Months Ended June 30, 2014
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Operating Activities
Net income	$	74,363		$	113,073		$	126,126		$	(236,697	)	$	76,865
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,927			—			104,808			—			107,735
Gain on sale of land parcel	—			—			(797		)	—			(797		)
Amortization of loan fees and costs	3,542			—			1,762			—			5,304
Amortization of debt premiums/discounts	80			—			56			—			136
Amortization of acquired above and below market leases	—			—			(1,434		)	—			(1,434		)
Deferred rent	—			—			(24,619		)	—			(24,619		)
Stock compensation expense	6,304			—			—			—			6,304
Equity in income related to subsidiaries	(119,860		)	(114,608		)	(2,229		)	236,697			—
Investment gains	—			—			(6,225		)	—			(6,225		)
Investment losses	—			1,535			3,705			—			5,240
Changes in operating assets and liabilities:
Restricted cash	(9		)	—			9			—			—
Tenant receivables	—			—			(735		)	—			(735		)
Deferred leasing costs	—			—			(17,452		)	—			(17,452		)
Other assets	(4,264		)	—			(1,652		)	—			(5,916		)
Accounts payable, accrued expenses, and tenant security deposits	20,850			—			(20,765		)	—			85
Net cash (used in) provided by operating activities	(16,067		)	—			160,558			—			144,491
Investing Activities
Proceeds from sale of properties	—			—			17,868			—			17,868
Additions to properties	—			—			(210,792		)	—			(210,792		)
Purchase of properties	—			—			(97,785		)	—			(97,785		)
Change in restricted cash related to construction projects	—			—			5,650			—			5,650
Contributions to unconsolidated real estate entity	—			—			(1,405		)	—			(1,405		)
Investments in subsidiaries	(235,931		)	(205,546		)	(8,095		)	449,572			—
Additions to investments	—			—			(25,358		)	—			(25,358		)
Proceeds from sales of investments	—			—			8,794			—			8,794
Proceeds from repayment of note receivable	—			—			29,851			—			29,851
Net cash used in investing activities	$	(235,931	)	$	(205,546	)	$	(281,272	)	$	449,572		$	(273,177	)
Condensed Consolidating Statement of Cash Flows (continued)
for the Six Months Ended June 30, 2014
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Financing Activities
Borrowings from secured notes payable	$	—		$	—		$	77,762		$	—		$	77,762
Repayments of borrowings from secured notes payable	—			—			(219,427		)	—			(219,427		)
Principal borrowings from unsecured senior line of credit	637,000			—			—			—			637,000
Repayments of borrowings from unsecured senior line of credit	(270,000		)	—			—			—			(270,000		)
Transfer to/from parent company	103			205,546			243,923			(449,572		)	—
Change in restricted cash related to financings	—			—			1,212			—			1,212
Deferred financing costs paid	(44		)	—			(266		)	—			(310		)
Dividends paid on common stock	(98,867		)	—			—			—			(98,867		)
Dividends paid on preferred stock	(12,943		)	—			—			—			(12,943		)
Contributions by noncontrolling interests	—			—			19,410			—			19,410
Distributions to noncontrolling interests	—			—			(1,388		)	—			(1,388		)
Distributions to redeemable noncontrolling interests	—			—			(595		)	—			(595		)
Net cash provided by financing activities	255,249			205,546			120,631			(449,572		)	131,854
Effect of foreign exchange rate changes on cash and cash equivalents	—			—			837			—			837
Net increase in cash and cash equivalents	3,251			—			754			—			4,005
Cash and cash equivalents at beginning of period	14,790			—			42,906			—			57,696
Cash and cash equivalents at end of period	$	18,041		$	—		$	43,660		$	—		$	61,701
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	$	22,218		$	—		$	9,704		$	—		$	31,922
Non-Cash Investing Activities
Change in accrued capital expenditures	$	—		$	—		$	592		$	—		$	592
Assumption of secured notes payable in connection with purchase of properties	$	—		$	—		$	(48,329	)	$	—		$	(48,329	)
Condensed Consolidating Statement of Cash Flows
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Operating Activities
Net income	$	61,612		$	96,042		$	107,721		$	(201,801	)	$	63,574
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,921			—			90,654			—			93,575
Loss on early extinguishment of debt	560			—			—			—			560
Gain on sale of land parcel	—			—			(772		)	—			(772		)
Loss on sale of real estate	—			—			121			—			121
Amortization of loan fees and costs	3,381			—			1,432			—			4,813
Amortization of debt premiums/discounts	31			—			206			—			237
Amortization of acquired above and below market leases	—			—			(1,660		)	—			(1,660		)
Deferred rent	—			—			(14,437		)	—			(14,437		)
Stock compensation expense	7,812			—			—			—			7,812
Equity in income related to subsidiaries	(103,719		)	(96,183		)	(1,899		)	201,801			—
Investment gains	—			(152		)	(2,514		)	—			(2,666		)
Investment losses	—			297			232			—			529
Changes in operating assets and liabilities:
Restricted cash	10			—			382			—			392
Tenant receivables	1			—			846			—			847
Deferred leasing costs	(792		)	—			(22,317		)	—			(23,109		)
Other assets	31,434			—			(25,512		)	188			6,110
Intercompany receivables and payables	(40		)	—			40			—			—
Accounts payable, accrued expenses, and tenant security deposits	(20,871		)	—			29,274			(188		)	8,215
Net cash (used in) provided by operating activities	(17,660		)	4			161,797			—			144,141
Investing Activities
Proceeds from sale of properties	10,796			—			91,019			—			101,815
Additions to properties	—			—			(298,927		)	—			(298,927		)
Change in restricted cash related to construction projects	—			—			(8,889		)	—			(8,889		)
Contributions to unconsolidated real estate entity	—			—			(4,889		)	—			(4,889		)
Loss in investments from unconsolidated real estate entity	—			—			(293		)	—			(293		)
Investments in subsidiaries	(61,214		)	(88,247		)	(1,243		)	150,704			—
Additions to investments	—			100			(14,933		)	—			(14,833		)
Proceeds from sales of investments	—			641			8,903			—			9,544
Net cash used in investing activities	$	(50,418	)	$	(87,506	)	$	(229,252	)	$	150,704		$	(216,472	)
Condensed Consolidating Statement of Cash Flows (continued)
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Financing Activities
Borrowings from secured notes payable	$	—		$	—		$	26,114		$	—		$	26,114
Repayments of borrowings from secured notes payable	—			—			(31,436		)	—			(31,436		)
Proceeds from issuance of senior notes payable	495,310			—			—			—			495,310
Principal borrowings from unsecured senior line of credit	305,000			—			—			—			305,000
Repayments of borrowings from unsecured senior line of credit	(871,000		)	—			—			—			(871,000		)
Repayments of unsecured senior bank term loans	(150,000		)	—			—			—			(150,000		)
Transfer to/from parent company	—			85,589			65,115			(150,704		)	—
Change in restricted cash related to financings	—			—			16,634			—			16,634
Deferred financing costs paid	(1,095		)	—			(362		)	—			(1,457		)
Proceeds from common stock offerings	534,469			—			—			—			534,469
Dividends paid on common stock	(73,932		)	—			—			—			(73,932		)
Dividends paid on preferred stock	(12,942		)	—			—			—			(12,942		)
Distributions to noncontrolling interests	—			—			(639		)	—			(639		)
Distributions to redeemable noncontrolling interests	—			—			(596		)	—			(596		)
Net cash provided by financing activities	225,810			85,589			74,830			(150,704		)	235,525
Effect of foreign exchange rate changes on cash and cash equivalents	—			—			(1,960		)	—			(1,960		)
Net increase (decrease) in cash and cash equivalents	157,732			(1,913		)	5,415			—			161,234
Cash and cash equivalents at beginning of period	98,567			1,913			40,491			—			140,971
Cash and cash equivalents at end of period	$	256,299		$	—		$	45,906		$	—		$	302,205
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	$	17,969		$	—		$	11,290		$	—		$	29,259
Non-Cash Investing Activities
Note receivable issued in connection with sale of real estate	$	29,820		$	—		$	9,000		$	—		$	38,820
Change in accrued capital expenditures	$	—		$	—		$	(48,198	)	$	—		$	(48,198	)

Basis_of_presentation_Policies

Basis of presentation (Policies)	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of presentation	'
	Basis of presentation
	We have prepared the accompanying interim consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) and in conformity with the rules and regulations of the Securities and Exchange Commission (“SEC”).  In our opinion, the interim consolidated financial statements presented herein reflect all adjustments that are necessary to fairly present the interim consolidated financial statements.  The results of operations for the interim period are not necessarily indicative of the results that may be expected for the year ending December 31, 2014.  These consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our annual report on Form 10-K for the year ended December 31, 2013.
	The accompanying consolidated financial statements include the accounts of Alexandria Real Estate Equities, Inc. and its consolidated subsidiaries. All significant intercompany balances and transactions have been eliminated.
	We hold interests, together with certain third parties, in companies that we consolidate in our financial statements. We consolidate the companies because we exercise significant control over major decisions by these entities, such as investment activity and changes in financing.
Reclassifications	'
	Reclassifications
	Certain prior period amounts have been reclassified to conform to the current period presentation for discontinued operations.
Use of estimates	'
	Use of estimates
	The preparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, and equity; the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements; and the amounts of revenues and expenses during the reporting period.  Actual results could materially differ from those estimates.
Investments in real estate, net, and discontinued operations	'
	Investments in real estate, net, and discontinued operations
	We recognize real estate acquired (including the intangible value of above or below market leases, acquired in-place leases, client tenant relationships, and other intangible assets or liabilities), liabilities assumed, and any noncontrolling interest in an acquired entity at their fair value as of the acquisition date.  If there is a bargain fixed-rate renewal option for the period beyond the non-cancelable lease term, we evaluate factors such as the business conditions in the industry in which the lessee operates, the economic conditions in the area in which the property is located, and the ability of the lessee to sublease the property during the renewal term, in order to determine the likelihood that the lessee will renew.  When we determine there is reasonable assurance that such bargain purchase option will be exercised, we consider its impact in determining the intangible value of such lease and its related amortization period.  The value of tangible assets acquired is based upon our estimation of value on an “as if vacant” basis.  The value of acquired in-place leases includes the estimated costs during the hypothetical lease-up period and other costs that would have been incurred in the execution of similar leases, considering market conditions at the acquisition date of the acquired in-place lease.  We assess the fair value of tangible and intangible assets based on numerous factors, including estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information.  Estimates of future cash flows are based on a number of factors, including the historical operating results, known trends, and market/economic conditions that may affect the property.  We also recognize the fair values of assets acquired, the liabilities assumed, and any noncontrolling interest in acquisitions of less than a 100% interest when the acquisition constitutes a change in control of the acquired entity.  Costs related to the acquisition of businesses, including real estate acquired with in-place leases, are expensed as incurred.
	The values allocated to buildings and building improvements, land improvements, tenant improvements, and equipment are depreciated on a straight-line basis using the shorter of the term of the respective ground lease and up to 40 years for buildings and building improvements, an estimated life of 20 years for land improvements, the respective lease term for tenant improvements, and the estimated useful life for equipment. The values of acquired above and below market leases are amortized over the lives of the related leases and recognized as either an increase (for below market leases) or a decrease (for above market leases) to rental income. The values of acquired in-place leases are classified in other assets in the accompanying consolidated balance sheets, and amortized over the remaining terms of the related leases.
	We are required to capitalize project costs, including predevelopment costs, interest, property taxes, insurance, and other costs directly related and essential to the acquisition, development, redevelopment, predevelopment, or construction of a project.  Capitalization of development, redevelopment, predevelopment, and construction costs is required while activities are ongoing to prepare an asset for its intended use.  Fluctuations in our development, redevelopment, predevelopment, and construction activities could result in significant changes to total expenses and net income.  Costs incurred after a project is substantially complete and ready for its intended use are expensed as incurred.  Should development, redevelopment, predevelopment, or construction activities cease, interest, property taxes, insurance, and certain other costs would no longer be eligible for capitalization and would be expensed as incurred.  Expenditures for repairs and maintenance are expensed as incurred.
	A property is classified as “held for sale” when all of the following criteria for a plan of sale have been met: (i) management, having the authority to approve the action, commits to a plan to sell the property; (ii) the property is available for immediate sale in its present condition, subject only to terms that are usual and customary; (iii) an active program to locate a buyer and other actions required to complete the plan to sell have been initiated; (iv) the sale of the property is probable and is expected to be completed within one year; (v) the property is being actively marketed for sale at a price that is reasonable in relation to its current fair value; and (vi) actions necessary to complete the plan of sale indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn.  When all of these criteria have been met, the property is classified as “held for sale,” and if (i) the operations and cash flows of the property have been or will be eliminated from the ongoing operations, and (ii) we will not have any significant continuing involvement in the operations of the property after the sale, then its operations, including any interest expense directly attributable to it, are classified as discontinued operations in our consolidated statements of income, and amounts for all prior periods presented are reclassified from continuing operations to discontinued operations.  Depreciation of assets ceases upon designation of a property as “held for sale.”
Impairment of long-lived assets	'
	Impairment of long-lived assets
	Long-lived assets to be held and used, including our rental properties, land held for development, construction in progress, and intangibles, are individually evaluated for impairment when conditions exist that may indicate that the amount of a long-lived asset may not be recoverable.  The amount of a long-lived asset to be held and used is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset.  Impairment indicators or triggering events for long-lived assets to be held and used, including our rental properties, land held for development, and construction in progress, are assessed by project and include significant fluctuations in estimated net operating income (“NOI”), occupancy changes, significant near-term lease expirations, current and historical operating and/or cash flow losses, construction costs, estimated completion dates, rental rates, and other market factors.  We assess the expected undiscounted cash flows based upon numerous factors, including, but not limited to, construction costs, available market information, current and historical operating results, known trends, current market/economic conditions that may affect the property, and our assumptions about the use of the asset, including, if necessary, a probability-weighted approach if multiple outcomes are under consideration.  Upon determination that an impairment has occurred, a write-down is recognized to reduce the carrying amount to its estimated fair value.  If an impairment loss is not required to be recognized, the recognition of depreciation is adjusted prospectively, as necessary, to reduce the carrying amount of the real estate to its estimated disposition value over the remaining period that the real estate is expected to be held and used.  We may adjust depreciation of properties that are expected to be disposed of or redeveloped prior to the end of their useful lives.
	We use the “held for sale” impairment model for our properties classified as “held for sale.”  The “held for sale” impairment model is different from the held and used impairment model.  Under the “held for sale” impairment model, an impairment loss is recognized if the amount of the long-lived asset classified as “held for sale” exceeds its fair value less cost to sell.  Because of these two different models, it is possible for a long-lived asset previously classified as held and used to require the recognition of an impairment charge upon classification as “held for sale.”
Investments	'
	Investments
	We hold equity investments in certain publicly traded companies and investments in certain privately held entities primarily involved in the life science industry.  All of our investments in actively traded public companies are considered “available for sale” and are reflected in the accompanying consolidated balance sheets at fair value.  Fair value has been determined based upon the closing price as of each balance sheet date, with unrealized gains and losses shown as a separate component of comprehensive income.  The classification of each investment is determined at the time each investment is made, and such determination is reevaluated at each balance sheet date.  The cost of each investment sold is determined by the specific identification method, with realized gains or losses classified in other income in the accompanying consolidated statements of income.  Investments in privately held entities and limited partnerships are generally accounted for under the cost method when our interest in the entity is so minor that we have virtually no influence over the entity’s operating and financial policies.  Certain investments in privately held entities and limited partnerships are accounted for under the equity method when our interest in the entity is not deemed so minor that we have virtually no influence over the entity’s operating and financial policies.  Under the equity method of accounting, we recognize our investment initially at cost and adjust the amount of the investment to recognize our share of the earnings or losses of the investee subsequent to the date of our investment.  Additionally, we limit our ownership percentage in the voting interest of each individual entity to less than 10%.  As of June 30, 2014, and December 31, 2013, our ownership percentage in the voting interest of each individual entity was less than 10%.
	We monitor each of our investments throughout the year for new developments, including operating results, results of clinical trials, capital-raising events, and merger and acquisition activities. Individual investments are evaluated for impairment when changes in conditions may indicate an impairment exists.  The factors that we consider in making these assessments include, but are not limited to, market prices, market conditions, available financing, prospects for favorable or unfavorable clinical trial results, new product initiatives, and new collaborative agreements.  If there are no identified events or changes in circumstances that would have an adverse effect on our cost method investments, we do not estimate the investment’s fair value.  For all of our investments, if a decline in the fair value of an investment below the carrying value is determined to be other than temporary, such investment is written down to its estimated fair value with a charge to current earnings.
Income Taxes	'
	Income taxes
	We are organized and qualify as a REIT pursuant to the Internal Revenue Code of 1986, as amended (the “Code”).  Under the Code, a REIT that distributes 100% of its REIT taxable income as a dividend to its shareholders each year and that meets certain other conditions is not subject to federal income taxes, but could be subject to certain state and local taxes.  We have distributed 100% or more of our taxable income.  Therefore, no provision for federal income taxes is required.  We file tax returns, including returns for our subsidiaries, with federal, state, and local jurisdictions, including jurisdictions located in the United States (“U.S.”), Canada, India, China, and other international locations.  Our tax returns are subject to examination in various jurisdictions for the calendar years 2009 through 2013.
Recognition of rental income and tenant recoveries	'
	Recognition of rental income and tenant recoveries
	Rental income from leases is recognized on a straight-line basis over the respective lease terms.  We classify amounts currently recognized as income, and expected to be received in later years, as an asset in deferred rent in the accompanying consolidated balance sheets.  Amounts received currently, but recognized as income in future years, are classified in accounts payable, accrued expenses, and tenant security deposits in the accompanying consolidated balance sheets.  We commence recognition of rental income at the date the property is ready for its intended use and the client tenant takes possession of or controls the physical use of the property.
	Tenant recoveries related to reimbursement of real estate taxes, insurance, utilities, repairs and maintenance, and other operating expenses are recognized as revenue in the period during which the applicable expenses are incurred.
	Tenant receivables consist primarily of amounts due for contractual lease payments, reimbursements of common area maintenance expenses, property taxes, and other expenses recoverable from client tenants.  Tenant receivables are expected to be collected within one year.  We may maintain an allowance for estimated losses that may result from the inability of our client tenants to make payments required under the terms of the lease and for tenant recoveries due.  If a client tenant fails to make contractual payments beyond any allowance, we may recognize additional bad debt expense in future periods equal to the amount of uncollectible rent and deferred rent receivables arising from the straight-lining of rent.  As of June 30, 2014, and December 31, 2013, we had no allowance for estimated losses.
Monitoring client tenant credit quality	'
	Monitoring client tenant credit quality
	During the term of each lease, we monitor the credit quality of our client tenants by (i) reviewing the credit rating of tenants that are rated by a nationally recognized credit rating agency, (ii) reviewing financial statements of the client tenants that are publicly available or that are required to be delivered to us pursuant to the applicable lease, (iii) monitoring news reports regarding our client tenants and their respective businesses, and (iv) monitoring the timeliness of lease payments. We have a team of employees who, among them, have graduate and undergraduate degrees in biology, chemistry, and industrial biotechnology and experience in the life science industry, as well as in finance. This research team is responsible for assessing and monitoring the credit quality of our client tenants and any material changes in credit quality.
Interest income	'
	Interest income
	Interest income was $911 thousand and $990 thousand during the three months ended June 30, 2014 and 2013, respectively. Interest income was $1.8 million and $2.3 million during the six months ended June 30, 2014 and 2013, respectively.  Interest income is included in other income in the accompanying consolidated statements of income.
Impact of recently issued accounting standards	'
	Impact of recently issued accounting standards
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update (“ASU”) on the reporting of discontinued operations, which raises the threshold for disposals to qualify as discontinued operations. Under this ASU, a discontinued operation is (i) a component of an entity or group of components that has been disposed of by sale, that has been disposed of other than by sale, or that is classified as “held for sale” and represents a strategic shift that has had or will have a major effect on an entity’s operations and financial results or (ii) an acquired business or nonprofit activity that is classified as “held for sale” on the date of the acquisition. A strategic shift that has or will have a major effect on an entity’s operations and financial results could include the disposal of (i) a major line of business, (ii) a major geographic area, (iii) a major equity method investment, or (iv) other major parts of an entity. Under current GAAP, an entity is prohibited from reporting a discontinued operation if it has certain continuing cash flows or involvement with the component after the disposal. This ASU eliminates these criteria and is effective for public companies during the interim and annual periods, beginning after December 15, 2014. We are required to adopt this ASU no later than January 1, 2015 and may early adopt this ASU during interim periods, as applicable. We expect the adoption of this ASU to result in fewer real estate sales qualifying for classification as discontinued operations in our consolidated financial statements.
	In May 2014, the FASB issued an ASU that replaces substantially all industry-specific revenue recognition requirements and converges areas under this topic with International Financial Reporting Standards. The ASU implements a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The ASU also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Other major provisions in this ASU include capitalizing and amortizing certain contract costs, ensuring the time value of money is considered in the applicable transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The ASU is effective for reporting periods beginning after December 15, 2016, and early adoption is prohibited. The ASU does not apply to lease contracts accounted for under current GAAP. We are currently evaluating the impact of the adoption of this ASU will have on our financial position and results of operations.

Investments_in_real_estate_net1

Investments in real estate, net (Tables)	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Investments in real estate	'
	Investments in real estate
	Our investments in real estate, consisted of the following as of June 30, 2014, and December 31, 2013 (in thousands):
		30-Jun-14			31-Dec-13
	Rental properties	$	6,668,458		$	6,442,208
	Less: accumulated depreciation	(1,039,810		)	(952,106		)
	Rental properties, net	5,628,648			5,490,102
	Construction in progress (“CIP”)/current value-creation projects:
	Current development in North America	613,104			558,482
	Current redevelopment in North America	32,139			8,856
	Current development in Asia	60,944			60,928
		706,187			628,266
		6,334,835			6,118,368
	Near-term value-creation projects in North America (CIP):
	50, 60, and 100 Binney Street	294,048			284,672
	Other projects	108,790			97,617
		402,838			382,289
	Future value-creation projects:
	North America	205,421			176,063
	Asia	79,328			77,251
		284,749			253,314
	Land subject to sale negotiations	7,695			22,943
	Investments in real estate	$	7,030,117		$	6,776,914

Investments_Tables

Investments (Tables)	6 Months Ended
	Jun. 30, 2014
Investments [Abstract]	'
Summary of investments	'
	The following table summarizes our investments as of June 30, 2014, and December 31, 2013 (in thousands):
		30-Jun-14				31-Dec-13
	“Available-for-sale” marketable equity securities, cost basis	$	12,937			$	2,879
	Unrealized gains	19,338			(1)	2,177
	Unrealized losses	(1,297		)		(587		)
	“Available-for-sale” marketable equity securities, at fair value	30,978				4,469
	Investments accounted for under cost method	143,824				135,819
	Total investments	$	174,802			$	140,288
	-1	The increase in our investments during the six months ended June 30, 2014, was primarily related to an increase in unrealized gains of approximately $16.0 million related to our investments in publicly traded life science companies. These unrealized gains are a component of our comprehensive income, within our stockholders’ equity, and have not been recognized in the accompanying consolidated statement of income for the six months ended June 30, 2014.
Schedule of net investment income	'
	The following table outlines our investment (loss) income, which is classified in other income in the accompanying consolidated statements of income (in thousands):
		Three Months Ended June 30,							Six Months Ended June 30,
		2014				2013			2014			2013
	Investment gains	$	2,185			$	2,220		$	6,225		$	2,666
	Investment losses	(3,546		)		(143		)	(5,240		)	(529		)
	Investment (loss) income	$	(1,361	)		$	2,077		$	985		$	2,137

Secured_and_unsecured_senior_d1

Secured and unsecured senior debt (Tables)	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Summary of secured and unsecured debt	'
	The following table summarizes our secured and unsecured senior debt as of June 30, 2014 (dollars in thousands):
		Fixed Rate/Hedged				Unhedged				Total				Weighted Average			Weighted Average
		Variable-Rate				Variable-Rate				Consolidated				Interest Rate at			Remaining Term
														End of Period (1)			(in years)
	Secured notes payable	$	415,655			$	199,896			$	615,551			4.83	%		3.2
	Unsecured senior notes payable	1,048,310				—				1,048,310				4.29			8.3
	$1.5 billion unsecured senior line of credit	—				571,000				571,000			(2)	1.25			4.5
	2016 Unsecured Senior Bank Term Loan	350,000				150,000				500,000			(2)	1.4			2.1
	2019 Unsecured Senior Bank Term Loan	600,000				—				600,000				2.05			4.5
	Total/weighted average	$	2,413,965			$	920,896			$	3,334,861			3.03	%		5.1
	Percentage of total debt	72		%		28		%		100		%
	-1	Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
	-2	These amounts do not reflect our unsecured senior notes payable offering completed on July 18, 2014. Net proceeds of $694 million were used to reduce variable-rate debt, including the partial repayment of $125 million of our 2016 Unsecured Senior Bank Term Loan and the reduction of $569 million of borrowings outstanding on our unsecured senior line of credit. See Note 13 – Subsequent Events, to our consolidated financial statements (unaudited) appearing elsewhere in this quarterly report on Form 10-Q for further information.
Detail of secured and unsecured debt	'
	The following table summarizes our outstanding consolidated indebtedness and respective principal maturities as of
	June 30, 2014 (dollars in thousands):
			Stated			Weighted Average			Maturity Date(2)		Principal Payments Remaining for the Period Ending December 31,
	Debt		Rate			Interest Rate(1)					2014				2015				2016				2017			2018			Thereafter			Total
	Secured notes payable
	San Diego		5.39	%		4	%		11/1/14		$	7,386			$	—			$	—			$	—		$	—		$	—		$	7,386
	Seattle		6			6			11/18/14		120				—				—				—			—			—			120
	Maryland		5.64			4.5			6/1/15		69				5,777				—				—			—			—			5,846
	San Francisco Bay Area		L+1.50			1.66			7/1/15		—				46,399				—				—			—			—			46,399
	Greater Boston, San Francisco Bay Area, and San Diego		5.73			5.73			1/1/16		862				1,816				75,501				—			—			—			78,179
	Greater Boston, San Diego, and New York City		5.82			5.82			4/1/16		465				988				29,389				—			—			—			30,842
	San Diego		5.74			3			4/15/16		83				175				6,916				—			—			—			7,174
	San Francisco Bay Area		L+1.40			1.56			6/1/16		—				—				11,936				—			—			—			11,936
	San Francisco Bay Area		6.35			6.35			8/1/16		1,229				2,652				126,715				—			—			—			130,596
	Maryland		2.14			2.14			1/20/17		—				—				—				76,000			—			—			76,000
	Greater Boston		L+1.35			1.5			8/23/17		—				—				—				65,440			—			—			65,440
	San Diego, Maryland, and Seattle		7.75			7.75			4/1/20		741				1,570				1,696				1,832			1,979			106,490			114,308
	San Diego		4.66			4.66			1/1/23		669				1,402				1,464				1,540			1,614			33,367			40,056
	San Francisco Bay Area		6.5			6.5			6/1/37		—				18				19				20			22			751			830
	Unamortized premiums										161				218				60				—			—			—			439
	Secured notes payable average/subtotal		4.89	%		4.83					11,785				61,015				253,696				144,832			3,615			140,608			615,551
	2016 Unsecured Senior Bank Term Loan		L+1.20	%		1.4			7/31/16		—				—				500,000				—			—			—			500,000
	2019 Unsecured Senior Bank Term Loan		L+1.20	%		2.05			1/3/19		—				—				—				—			—			600,000			600,000
	$1.5 billion unsecured senior line of credit		L+1.10	%	(3)	1.25			1/3/19		—				—				—				—			—			571,000			571,000
	Unsecured senior notes payable		4.6	%		4.61			4/1/22		—				—				—				—			—			550,000			550,000
	Unsecured senior notes payable		3.9	%		3.94			6/15/23		—				—				—				—			—			500,000			500,000
	Unamortized discounts										(82		)		(170		)		(177		)		(184		)	(192		)	(885		)	(1,690		)
	Unsecured debt average/subtotal					2.63					(82		)		(170		)		499,823				(184		)	(192		)	2,220,115			2,719,310
	Average/total					3.03	%				$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	Balloon payments										$	7,339			$	52,139			$	748,836			$	141,440		$	—		$	2,351,238		$	3,300,992
	Principal amortization										4,364				8,706				4,683				3,208			3,423			9,485			33,869
	Total consolidated debt										$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	Fixed-rate/hedged variable-rate debt										$	11,583			$	14,446			$	591,582			$	3,208		$	3,423		$	1,789,723		$	2,413,965
	Unhedged variable-rate debt										120				46,399				161,937				141,440			—			571,000			920,896
	Total consolidated debt										$	11,703			$	60,845			$	753,519			$	144,648		$	3,423		$	2,360,723		$	3,334,861
	-1	Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
	-2	Includes any extension options that we control.
	-3	In addition to the stated rate, the unsecured senior line of credit is subject to an annual facility fee of 0.20%.
Schedule of interest expense	'
	The following table summarizes interest expense for the three and six months ended June 30, 2014 and 2013 (in thousands):
		Three Months Ended June 30,								Six Months Ended June 30,
		2014				2013				2014				2013
	Gross interest	$	28,735			$	31,668			$	59,871			$	63,709
	Capitalized interest	(11,302		)		(15,690		)		(23,315		)		(29,711		)
	Interest expense	$	17,433			$	15,978			$	36,556			$	33,998
Schedule of secured construction loans	'
	The following table summarizes our secured construction loans as of June 30, 2014 (dollars in thousands):
	Address		Market		Stated Rate				Maturity Date				Outstanding Balance				Remaining Commitments				Total Aggregate Commitments
	259 East Grand Avenue		San Francisco Bay Area			L+1.50	%		7/1/15		(1)		$	46,399			$	8,601			$	55,000
	269 East Grand Avenue		San Francisco Bay Area			L+1.40	%		6/1/16		(2)		11,936				24,064				36,000
	75/125 Binney Street		Greater Boston			L+1.35	%		8/23/17		(3)		65,440				184,960				250,400
													$	123,775			$	217,625			$	341,400
	-1	We have two, one-year options to extend the stated maturity date to July 1, 2017, subject to certain conditions.
	-2	We have two, one-year options to extend the stated maturity date to June 1, 2018, subject to certain conditions.
	-3	We have a one-year option to extend the stated maturity date to August 23, 2018, subject to certain conditions.

Interest_rate_swap_agreements_

Interest rate swap agreements (Tables)	6 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Outstanding interest rate hedge agreements designated as cash flow hedges of interest rate risk	'
	We had the following outstanding interest rate swap agreements that were designated as cash flow hedges of interest rate risk as of June 30, 2014 (dollars in thousands):
	Effective Date		Maturity Date	Number of Contracts	Weighted Average Interest Pay	Fair Value as of 6/30/14			Notional Amount in Effect as of
					Rate (1)				6/30/14		12/31/14		12/31/15		12/31/16
	31-Dec-13		31-Dec-14	2	0.98%	$	(2,114	)	$	500,000	$	—	$	—	$	—
	31-Dec-13		31-Mar-15	2	0.23%	(144		)	250,000		250,000		—		—
	31-Mar-14		31-Mar-15	4	0.21%	(75		)	200,000		200,000		—		—
	31-Dec-14		31-Mar-16	3	0.53%	(335		)	—		500,000		500,000		—
	31-Mar-16		31-Mar-17	3	1.40%	46			—		—		—		500,000
	Total					$	(2,622	)	$	950,000	$	950,000	$	500,000	$	500,000
	-1	In addition to the interest pay rate, borrowings outstanding as of June 30, 2014, under our unsecured senior bank term loans include an applicable margin of 1.20% and borrowings outstanding under our unsecured senior line of credit include an applicable margin of 1.10%.

Fair_value_measurements_Tables

Fair value measurements (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of fair value of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy	'
	The following tables set forth the assets and liabilities that we measure at fair value on a recurring basis by level within the fair value hierarchy as of June 30, 2014, and December 31, 2013 (in thousands):
						30-Jun-14
	Description		Total			Quoted Prices in			Significant			Significant
						Active Markets			Other			Unobservable
						for Identical			Observable			Inputs
						Assets			Inputs
	Assets:
	“Available-for-sale” securities		$	30,978		$	30,978		$	—		$	—
	Interest rate swap agreements		$	46		$	—		$	46		$	—
	Liabilities:
	Interest rate swap agreements		$	2,668		$	—		$	2,668		$	—
						31-Dec-13
	Description		Total			Quoted Prices in			Significant			Significant
						Active Markets			Other			Unobservable
						for Identical			Observable			Inputs
						Assets			Inputs
	Assets:
	“Available-for-sale” securities		$	4,469		$	4,469		$	—		$	—
	Interest rate swap agreements		$	2,870		$	—		$	2,870		$	—
	Liabilities:
	Interest rate swap agreements		$	6,191		$	—		$	6,191		$	—
Schedule of the book and fair values of our marketable securities, interest rate swap agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loan	'
	As of June 30, 2014, and December 31, 2013, the book and fair values of our “available-for-sale” marketable equity securities, interest rate swap agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loans were as follows (in thousands):
		30-Jun-14						31-Dec-13
		Book Value			Fair Value			Book Value			Fair Value
	Assets:
	“Available-for-sale” marketable equity securities	$	30,978		$	30,978		$	4,469		$	4,469
	Interest rate swap agreements	$	46		$	46		$	2,870		$	2,870
	Liabilities:
	Interest rate swap agreements	$	2,668		$	2,668		$	6,191		$	6,191
	Secured notes payable	$	615,551		$	664,724		$	708,831		$	736,772
	Unsecured senior notes payable	$	1,048,310		$	1,081,305		$	1,048,230		$	1,043,125
	Unsecured senior line of credit	$	571,000		$	570,393		$	204,000		$	193,714
	Unsecured senior bank term loans	$	1,100,000		$	1,099,326		$	1,100,000		$	1,099,897

Earnings_per_share_Tables

Earnings per share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Reconciliation of the numerators and denominators of the basic and diluted earnings per share computations	'
	The table below is a reconciliation of the numerators and denominators of the basic and diluted earnings per share computations for the three and six months ended June 30, 2014 and 2013 (dollars in thousands, except per share amounts):
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Income from continuing operations	$	35,466		$	32,316		$	76,377		$	61,716
	Gain on sale of land parcel	797			772			797			772
	Dividends on preferred stock	(6,472		)	(6,471		)	(12,943		)	(12,942		)
	Net income attributable to noncontrolling interests	(1,307		)	(980		)	(2,502		)	(1,962		)
	Net income attributable to unvested restricted stock awards	(405		)	(403		)	(779		)	(745		)
	Income from continuing operations attributable to Alexandria’s common stockholders – basic and diluted	28,079			25,234			60,950			46,839
	(Loss) income from discontinued operations	(147		)	249			(309		)	1,086
	Net income attributable to Alexandria’s common stockholders – basic and diluted	$	27,932		$	25,483		$	60,641		$	47,925
	Weighted average shares of common stock outstanding – basic and diluted	71,126			66,973			71,100			65,078
	Earnings per share attributable to Alexandria’s common stockholders – basic and diluted:
	Continuing operations	$	0.39		$	0.38		$	0.85		$	0.72
	Discontinued operations	—			—			—			0.02
	Earnings per share – basic and diluted	$	0.39		$	0.38		$	0.85		$	0.74

Net_income_attributable_to_Ale1

Net income attributable to Alexandria Real Estate Equities, Inc. (Tables)	6 Months Ended
	Jun. 30, 2014
Net Income (Loss) Attributable to Parent [Abstract]	'
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.	'
	The following table presents income from continuing and discontinued operations attributable to Alexandria Real Estate Equities, Inc. for the three and six months ended June 30, 2014 and 2013 (in thousands):
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Income from continuing operations	$	35,466		$	32,316		$	76,377		$	61,716
	Gain on sale of land parcel	797			772			797			772
	Less: net income attributable to noncontrolling interests	(1,307		)	(980		)	(2,502		)	(1,962		)
	Income from continuing operations attributable to Alexandria Real Estate Equities, Inc.	34,956			32,108			74,672			60,526
	(Loss) income from discontinued operations	(147		)	249			(309		)	1,086
	Net income attributable to Alexandria Real Estate Equities, Inc.	$	34,809		$	32,357		$	74,363		$	61,612

Stockholders_equity_Tables

Stockholders' equity (Tables)	6 Months Ended
	Jun. 30, 2014
Stockholders' Equity Note [Abstract]	'
Accumulated other comprehensive loss attributable to Alexandria Real Estate Equities, Inc.	'
	Accumulated other comprehensive loss
	Accumulated other comprehensive loss attributable to Alexandria Real Estate Equities, Inc. consists of the following (in thousands):
		Unrealized Gain on Marketable Securities		Unrealized Loss on Interest Rate			Unrealized Loss on Foreign Currency Translation			Total
				Swap Agreements
	Balance as of December 31, 2013	$	1,590	$	(3,321	)	$	(34,473	)	$	(36,204	)
	Other comprehensive income before reclassifications	16,045		(3,914		)	2,809			14,940
	Amounts reclassified from other comprehensive income	406		4,613			—			5,019
	Net other comprehensive income	16,451		699			2,809			19,959
	Balance as of June 30, 2014	$	18,041	$	(2,622	)	$	(31,664	)	$	(16,245	)

Discontinued_operations_Tables

Discontinued operations (Tables)	6 Months Ended
	Jun. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Summary of net assets of discontinued operations and (loss) income from discontinued operations, net	'
	The following is a summary of net assets of discontinued operations and (loss) income from discontinued operations (in thousands):
		June 30, 2014				December 31, 2013
	Properties “held for sale,” net	$	7,651			$	7,644
	Other assets	35				103
	Total assets	7,686				7,747
	Total liabilities	(135		)		(266		)
	Net assets of discontinued operations	$	7,551			$	7,481
			Three Months Ended June 30,							Six Months Ended June 30,
			2014				2013			2014			2013
	Total revenues		$	—			$	546		$	—		$	4,339
	Operating expenses		147				280			309			1,730
	Total revenues less operating expenses from discontinued operations		(147		)		266			(309		)	2,609
	Depreciation expense		—				236			—			1,402
	(Gain) loss on sale of real estate		—				(219		)	—			121
	(Loss) income from discontinued operations (1)		$	(147	)		$	249		$	(309	)	$	1,086
	-1	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Condensed_consolidating_financ1

Condensed consolidating financial information (Tables)	6 Months Ended
	Jun. 30, 2014
Condensed Consolidated Financial Information [Abstract]	'
Condensed consolidating balance sheet	'
	Consolidating Balance Sheet
	as of June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria Real Estate Equities, Inc.			Alexandria			Combined			Eliminations			Consolidated
		(Issuer)			Real Estate			Non-
					Equities, L.P.			Guarantor
					(Guarantor			Subsidiaries
					Subsidiary)
	Assets
	Investments in real estate	$	—		$	—		$	7,030,117		$	—		$	7,030,117
	Cash and cash equivalents	18,041			—			43,660			—			61,701
	Restricted cash	64			—			24,455			—			24,519
	Tenant receivables	—			—			10,654			—			10,654
	Deferred rent	—			—			214,793			—			214,793
	Deferred leasing and financing costs	33,298			—			160,323			—			193,621
	Investments	—			9,637			165,165			—			174,802
	Investments in and advances to affiliates	6,678,756			6,162,162			125,591			(12,966,509		)	—
	Other assets	18,740			—			86,702			—			105,442
	Total assets	$	6,748,899		$	6,171,799		$	7,861,460		$	(12,966,509	)	$	7,815,649
	Liabilities, Noncontrolling Interests, and Equity
	Secured notes payable	$	—		$	—		$	615,551		$	—		$	615,551
	Unsecured senior notes payable	1,048,310			—			—			—			1,048,310
	Unsecured senior line of credit	571,000			—			—			—			571,000
	Unsecured senior bank term loans	1,100,000			—			—			—			1,100,000
	Accounts payable, accrued expenses, and tenant security deposits	65,700			—			368,828			—			434,528
	Dividends payable	57,087			—			290			—			57,377
	Total liabilities	2,842,097			—			984,669			—			3,826,766
	Redeemable noncontrolling interests	—			—			14,381			—			14,381
	Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,906,802			6,171,799			6,794,710			(12,966,509		)	3,906,802
	Noncontrolling interests	—			—			67,700			—			67,700
	Total equity	3,906,802			6,171,799			6,862,410			(12,966,509		)	3,974,502
	Total liabilities, noncontrolling interests, and equity	$	6,748,899		$	6,171,799		$	7,861,460		$	(12,966,509	)	$	7,815,649
	Condensed Consolidating Balance Sheet
	as of December 31, 2013
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Assets
	Investments in real estate	$	—		$	—		$	6,776,914		$	—		$	6,776,914
	Cash and cash equivalents	14,790			—			42,906			—			57,696
	Restricted cash	55			—			27,654			—			27,709
	Tenant receivables	—			—			9,918			—			9,918
	Deferred rent	—			—			190,425			—			190,425
	Deferred leasing and financing costs	36,901			—			155,757			—			192,658
	Investments	—			10,868			129,420			—			140,288
	Investments in and advances to affiliates	6,299,551			5,823,058			119,421			(12,242,030		)	—
	Other assets	20,226			—			113,930			—			134,156
	Total assets	$	6,371,523		$	5,833,926		$	7,566,345		$	(12,242,030	)	$	7,529,764
	Liabilities, Noncontrolling Interests, and Equity
	Secured notes payable	$	—		$	—		$	708,831		$	—		$	708,831
	Unsecured senior notes payable	1,048,230			—			—			—			1,048,230
	Unsecured senior line of credit	204,000			—			—			—			204,000
	Unsecured senior bank term loans	1,100,000			—			—			—			1,100,000
	Accounts payable, accrued expenses, and tenant security deposits	48,373			—			386,969			—			435,342
	Dividends payable	54,131			—			289			—			54,420
	Total liabilities	2,454,734			—			1,096,089			—			3,550,823
	Redeemable noncontrolling interests	—			—			14,444			—			14,444
	Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,916,789			5,833,926			6,408,104			(12,242,030		)	3,916,789
Noncontrolling interests	—			—			47,708			—			47,708
Total equity	3,916,789			5,833,926			6,455,812			(12,242,030		)	3,964,497
Total liabilities, noncontrolling interests, and equity	$	6,371,523		$	5,833,926		$	7,566,345		$	(12,242,030	)	$	7,529,764
Condensed consolidating statements of income	'
	Condensed Consolidating Statement of Income
	for the Three Months Ended June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Revenues:
	Rental	$	—		$	—		$	134,992		$	—		$	134,992
	Tenant recoveries	—			—			40,944			—			40,944
	Other income	2,916			(1,535		)	2,532			(3,447		)	466
	Total revenues	2,916			(1,535		)	178,468			(3,447		)	176,402
	Expenses:
	Rental operations	—			—			52,353			—			52,353
	General and administrative	11,506			—			5,777			(3,447		)	13,836
	Interest	12,493			—			4,940			—			17,433
	Depreciation and amortization	1,456			—			55,858			—			57,314
	Total expenses	25,455			—			118,928			(3,447		)	140,936
	(Loss) income from continuing operations before equity in earnings of affiliates	(22,539		)	(1,535		)	59,540			—			35,466
	Equity in earnings of affiliates	57,355			56,302			1,081			(114,738		)	—
	Income from continuing operations	34,816			54,767			60,621			(114,738		)	35,466
	Loss from discontinued operations	(7		)	—			(140		)	—			(147		)
	Gain on sale of land parcel	—			—			797			—			797
	Net income	34,809			54,767			61,278			(114,738		)	36,116
	Dividends on preferred stock	(6,472		)	—			—			—			(6,472		)
	Net income attributable to noncontrolling interests	—			—			(1,307		)	—			(1,307		)
	Net income attributable to unvested restricted stock awards	(405		)	—			—			—			(405		)
	Net income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	27,932		$	54,767		$	59,971		$	(114,738	)	$	27,932
	Condensed Consolidating Statement of Income
	for the Three Months Ended June 30, 2013
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Revenues:
	Rental	$	—		$	—		$	114,493		$	—		$	114,493
	Tenant recoveries	—			—			35,869			—			35,869
	Other income	2,674			(75		)	4,098			(3,129		)	3,568
	Total revenues	2,674			(75		)	154,460			(3,129		)	153,930
	Expenses:
	Rental operations	—			—			46,277			—			46,277
	General and administrative	12,164			—			3,420			(3,129		)	12,455
	Interest	10,090			—			5,888			—			15,978
	Depreciation and amortization	1,446			—			44,898			—			46,344
	Loss on early extinguishment of debt	560			—			—			—			560
	Total expenses	24,260			—			100,483			(3,129		)	121,614
	(Loss) income from continuing operations before equity in earnings of affiliates	(21,586		)	(75		)	53,977			—			32,316
	Equity in earnings of affiliates	53,912			48,944			939			(103,795		)	—
	Income from continuing operations	32,326			48,869			54,916			(103,795		)	32,316
	Income from discontinued operations	31			—			218			—			249
	Gain on sale of land parcel	—			—			772			—			772
	Net income	32,357			48,869			55,906			(103,795		)	33,337
	Dividends on preferred stock	(6,471		)	—			—			—			(6,471		)
	Net income attributable to noncontrolling interests	—			—			(980		)	—			(980		)
	Net income attributable to unvested restricted stock awards	(403		)	—			—			—			(403		)
	Net income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	25,483		$	48,869		$	54,926		$	(103,795	)	$	25,483
Condensed consolidating statement comprehensive income	'
	Condensed Consolidating Statement of Comprehensive Income
	for the Three Months Ended June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Net income	$	34,809		$	54,767		$	61,278		$	(114,738	)	$	36,116
	Other comprehensive income:
	Unrealized gains (losses) on marketable securities:
	Unrealized holding gains (losses) arising during the period	—			310			(3,044		)	—			(2,734		)
	Reclassification adjustment for losses included in net income	—			—			406			—			406
	Unrealized gains (losses) on marketable securities, net	—			310			(2,638		)	—			(2,328		)
	Unrealized gains on interest rate swap agreements:
	Unrealized interest rate swap losses arising during the period	(2,526		)	—			—			—			(2,526		)
	Reclassification adjustment for amortization of interest expense included in net income	1,123			—			—			—			1,123
	Unrealized losses on interest rate swap agreements	(1,403		)	—			—			—			(1,403		)
	Foreign currency translation gains	—			—			5,915			—			5,915
	Total other comprehensive (loss) income	(1,403		)	310			3,277			—			2,184
	Comprehensive income	33,406			55,077			64,555			(114,738		)	38,300
	Less: comprehensive income attributable to noncontrolling interests	—			—			(1,307		)	—			(1,307		)
	Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	33,406		$	55,077		$	63,248		$	(114,738	)	$	36,993
	Condensed Consolidating Statement of Comprehensive Income
	for the Three Months Ended June 30, 2013
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Net income	$	32,357		$	48,869		$	55,906		$	(103,795	)	$	33,337
	Other comprehensive income:
	Unrealized (losses) gains on marketable securities:
	Unrealized holding (losses) gains arising during the period	—			(244		)	288			—			44
	Reclassification adjustment for losses (gains) included in net income	—			106			(64		)	—			42
	Unrealized (losses) gains on marketable securities	—			(138		)	224			—			86
	Unrealized gains on interest rate swap agreements:
	Unrealized interest rate swap losses arising during the period	105			—			—			—			105
	Reclassification adjustment for amortization of interest expense included in net income	3,834			—			—			—			3,834
	Unrealized gains on interest rate swap agreements	3,939			—			—			—			3,939
	Foreign currency translation losses	—			—			(20,698		)	—			(20,698		)
	Total other comprehensive income (loss)	3,939			(138		)	(20,474		)	—			(16,673		)
	Comprehensive income	36,296			48,731			35,432			(103,795		)	16,664
	Less: comprehensive income attributable to noncontrolling interests	—			—			(1,008		)	—			(1,008		)
	Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	36,296		$	48,731		$	34,424		$	(103,795	)	$	15,656
	Condensed Consolidating Statement of Comprehensive Income
	for the Six Months Ended June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria			Alexandria			Combined			Eliminations			Consolidated
		Real Estate			Real Estate			Non-
		Equities, Inc.			Equities, L.P.			Guarantor
		(Issuer)			(Guarantor			Subsidiaries
					Subsidiary)
	Net income	$	74,363		$	113,073		$	126,126		$	(236,697	)	$	76,865
	Other comprehensive income:
	Unrealized gains on marketable securities:
	Unrealized holding gains arising during the period	—			310			15,735			—			16,045
	Reclassification adjustment for losses included in net income	—			—			406			—			406
	Unrealized gains on marketable securities	—			310			16,141			—			16,451
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap gains arising during the period	(3,914		)	—			—			—			(3,914		)
Reclassification adjustment for amortization of interest expense included in net income	4,613			—			—			—			4,613
Unrealized gains on interest rate swap agreements	699			—			—			—			699
Foreign currency translation gains	—			—			2,809			—			2,809
Total other comprehensive income	699			310			18,950			—			19,959
Comprehensive income	75,062			113,383			145,076			(236,697		)	96,824
Less: comprehensive income attributable to noncontrolling interests	—			—			(2,502		)	—			(2,502		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	75,062		$	113,383		$	142,574		$	(236,697	)	$	94,322
Condensed Consolidating Statement of Comprehensive Income
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria			Alexandria			Combined			Eliminations			Consolidated
	Real Estate			Real Estate			Non-
	Equities, Inc.			Equities, L.P.			Guarantor
	(Issuer)			(Guarantor			Subsidiaries
				Subsidiary)
Net income	$	61,612		$	96,042		$	107,721		$	(201,801	)	$	63,574
Other comprehensive income:
Unrealized gains on marketable securities:
Unrealized holding gains (losses) arising during the period	—			405			(45		)	—			360
Reclassification adjustment for (gains) losses included in net income	—			(375		)	145			—			(230		)
Unrealized gains on marketable securities	—			30			100			—			130
Unrealized gains on interest rate swap agreements:
Unrealized interest rate swap losses arising during the period	(28		)	—			—			—			(28		)
Reclassification adjustment for amortization of interest expense included in net income	8,142			—			—			—			8,142
Unrealized gains on interest rate swap agreements	8,114			—			—			—			8,114
Foreign currency translation losses	—			—			(23,057		)	—			(23,057		)
Total other comprehensive income (loss)	8,114			30			(22,957		)	—			(14,813		)
Comprehensive income	69,726			96,072			84,764			(201,801		)	48,761
Less: comprehensive income attributable to noncontrolling interests	—			—			(1,906		)	—			(1,906		)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$	69,726		$	96,072		$	82,858		$	(201,801	)	$	46,855
Condensed consolidating statement cash flows	'
	Condensed Consolidating Statement of Cash Flows
	for the Six Months Ended June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
		Estate Equities,			Estate Equities,			Non-Guarantor
		Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
					Subsidiary)
	Operating Activities
	Net income	$	74,363		$	113,073		$	126,126		$	(236,697	)	$	76,865
	Adjustments to reconcile net income to net cash provided by operating activities:
	Depreciation and amortization	2,927			—			104,808			—			107,735
	Gain on sale of land parcel	—			—			(797		)	—			(797		)
	Amortization of loan fees and costs	3,542			—			1,762			—			5,304
	Amortization of debt premiums/discounts	80			—			56			—			136
	Amortization of acquired above and below market leases	—			—			(1,434		)	—			(1,434		)
	Deferred rent	—			—			(24,619		)	—			(24,619		)
	Stock compensation expense	6,304			—			—			—			6,304
	Equity in income related to subsidiaries	(119,860		)	(114,608		)	(2,229		)	236,697			—
	Investment gains	—			—			(6,225		)	—			(6,225		)
	Investment losses	—			1,535			3,705			—			5,240
	Changes in operating assets and liabilities:
	Restricted cash	(9		)	—			9			—			—
	Tenant receivables	—			—			(735		)	—			(735		)
	Deferred leasing costs	—			—			(17,452		)	—			(17,452		)
	Other assets	(4,264		)	—			(1,652		)	—			(5,916		)
	Accounts payable, accrued expenses, and tenant security deposits	20,850			—			(20,765		)	—			85
	Net cash (used in) provided by operating activities	(16,067		)	—			160,558			—			144,491
	Investing Activities
	Proceeds from sale of properties	—			—			17,868			—			17,868
	Additions to properties	—			—			(210,792		)	—			(210,792		)
	Purchase of properties	—			—			(97,785		)	—			(97,785		)
	Change in restricted cash related to construction projects	—			—			5,650			—			5,650
	Contributions to unconsolidated real estate entity	—			—			(1,405		)	—			(1,405		)
	Investments in subsidiaries	(235,931		)	(205,546		)	(8,095		)	449,572			—
	Additions to investments	—			—			(25,358		)	—			(25,358		)
	Proceeds from sales of investments	—			—			8,794			—			8,794
	Proceeds from repayment of note receivable	—			—			29,851			—			29,851
	Net cash used in investing activities	$	(235,931	)	$	(205,546	)	$	(281,272	)	$	449,572		$	(273,177	)
	Condensed Consolidating Statement of Cash Flows (continued)
	for the Six Months Ended June 30, 2014
	(In thousands)
	(Unaudited)
		Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
		Estate Equities,			Estate Equities,			Non-Guarantor
		Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
					Subsidiary)
	Financing Activities
	Borrowings from secured notes payable	$	—		$	—		$	77,762		$	—		$	77,762
	Repayments of borrowings from secured notes payable	—			—			(219,427		)	—			(219,427		)
	Principal borrowings from unsecured senior line of credit	637,000			—			—			—			637,000
	Repayments of borrowings from unsecured senior line of credit	(270,000		)	—			—			—			(270,000		)
	Transfer to/from parent company	103			205,546			243,923			(449,572		)	—
	Change in restricted cash related to financings	—			—			1,212			—			1,212
	Deferred financing costs paid	(44		)	—			(266		)	—			(310		)
	Dividends paid on common stock	(98,867		)	—			—			—			(98,867		)
	Dividends paid on preferred stock	(12,943		)	—			—			—			(12,943		)
	Contributions by noncontrolling interests	—			—			19,410			—			19,410
	Distributions to noncontrolling interests	—			—			(1,388		)	—			(1,388		)
	Distributions to redeemable noncontrolling interests	—			—			(595		)	—			(595		)
	Net cash provided by financing activities	255,249			205,546			120,631			(449,572		)	131,854
	Effect of foreign exchange rate changes on cash and cash equivalents	—			—			837			—			837
	Net increase in cash and cash equivalents	3,251			—			754			—			4,005
Cash and cash equivalents at beginning of period	14,790			—			42,906			—			57,696
Cash and cash equivalents at end of period	$	18,041		$	—		$	43,660		$	—		$	61,701
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	$	22,218		$	—		$	9,704		$	—		$	31,922
Non-Cash Investing Activities
Change in accrued capital expenditures	$	—		$	—		$	592		$	—		$	592
Assumption of secured notes payable in connection with purchase of properties	$	—		$	—		$	(48,329	)	$	—		$	(48,329	)
Condensed Consolidating Statement of Cash Flows
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Operating Activities
Net income	$	61,612		$	96,042		$	107,721		$	(201,801	)	$	63,574
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,921			—			90,654			—			93,575
Loss on early extinguishment of debt	560			—			—			—			560
Gain on sale of land parcel	—			—			(772		)	—			(772		)
Loss on sale of real estate	—			—			121			—			121
Amortization of loan fees and costs	3,381			—			1,432			—			4,813
Amortization of debt premiums/discounts	31			—			206			—			237
Amortization of acquired above and below market leases	—			—			(1,660		)	—			(1,660		)
Deferred rent	—			—			(14,437		)	—			(14,437		)
Stock compensation expense	7,812			—			—			—			7,812
Equity in income related to subsidiaries	(103,719		)	(96,183		)	(1,899		)	201,801			—
Investment gains	—			(152		)	(2,514		)	—			(2,666		)
Investment losses	—			297			232			—			529
Changes in operating assets and liabilities:
Restricted cash	10			—			382			—			392
Tenant receivables	1			—			846			—			847
Deferred leasing costs	(792		)	—			(22,317		)	—			(23,109		)
Other assets	31,434			—			(25,512		)	188			6,110
Intercompany receivables and payables	(40		)	—			40			—			—
Accounts payable, accrued expenses, and tenant security deposits	(20,871		)	—			29,274			(188		)	8,215
Net cash (used in) provided by operating activities	(17,660		)	4			161,797			—			144,141
Investing Activities
Proceeds from sale of properties	10,796			—			91,019			—			101,815
Additions to properties	—			—			(298,927		)	—			(298,927		)
Change in restricted cash related to construction projects	—			—			(8,889		)	—			(8,889		)
Contributions to unconsolidated real estate entity	—			—			(4,889		)	—			(4,889		)
Loss in investments from unconsolidated real estate entity	—			—			(293		)	—			(293		)
Investments in subsidiaries	(61,214		)	(88,247		)	(1,243		)	150,704			—
Additions to investments	—			100			(14,933		)	—			(14,833		)
Proceeds from sales of investments	—			641			8,903			—			9,544
Net cash used in investing activities	$	(50,418	)	$	(87,506	)	$	(229,252	)	$	150,704		$	(216,472	)
Condensed Consolidating Statement of Cash Flows (continued)
for the Six Months Ended June 30, 2013
(In thousands)
(Unaudited)
	Alexandria Real			Alexandria Real			Combined			Eliminations			Consolidated
	Estate Equities,			Estate Equities,			Non-Guarantor
	Inc. (Issuer)			L.P. (Guarantor			Subsidiaries
				Subsidiary)
Financing Activities
Borrowings from secured notes payable	$	—		$	—		$	26,114		$	—		$	26,114
Repayments of borrowings from secured notes payable	—			—			(31,436		)	—			(31,436		)
Proceeds from issuance of senior notes payable	495,310			—			—			—			495,310
Principal borrowings from unsecured senior line of credit	305,000			—			—			—			305,000
Repayments of borrowings from unsecured senior line of credit	(871,000		)	—			—			—			(871,000		)
Repayments of unsecured senior bank term loans	(150,000		)	—			—			—			(150,000		)
Transfer to/from parent company	—			85,589			65,115			(150,704		)	—
Change in restricted cash related to financings	—			—			16,634			—			16,634
Deferred financing costs paid	(1,095		)	—			(362		)	—			(1,457		)
Proceeds from common stock offerings	534,469			—			—			—			534,469
Dividends paid on common stock	(73,932		)	—			—			—			(73,932		)
Dividends paid on preferred stock	(12,942		)	—			—			—			(12,942		)
Distributions to noncontrolling interests	—			—			(639		)	—			(639		)
Distributions to redeemable noncontrolling interests	—			—			(596		)	—			(596		)
Net cash provided by financing activities	225,810			85,589			74,830			(150,704		)	235,525
Effect of foreign exchange rate changes on cash and cash equivalents	—			—			(1,960		)	—			(1,960		)
Net increase (decrease) in cash and cash equivalents	157,732			(1,913		)	5,415			—			161,234
Cash and cash equivalents at beginning of period	98,567			1,913			40,491			—			140,971
Cash and cash equivalents at end of period	$	256,299		$	—		$	45,906		$	—		$	302,205
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	$	17,969		$	—		$	11,290		$	—		$	29,259
Non-Cash Investing Activities
Note receivable issued in connection with sale of real estate	$	29,820		$	—		$	9,000		$	—		$	38,820
Change in accrued capital expenditures	$	—		$	—		$	(48,198	)	$	—		$	(48,198	)

Background_Details

Background (Details) (USD $)	6 Months Ended
In Billions, unless otherwise specified	Jun. 30, 2014
Nature of Business [Line Items]	'
Total Market Capitalization	9.3
Total Rentable Square Footage of Asset Base	31,378,329
Area of Real Estate Property	17,881,108
Square Footage of Real Estate Property, Future Development	13,497,221
Investment-grade client tenants as a percentage of total annualized base rent	52.00%
Percentage of leases containing effective annual rent escalations	96.00%
Percentage of leases which are triple net leases	94.00%
Percentage of leases providing for recapture of certain capital expenditures	93.00%
Minimum	'
Nature of Business [Line Items]	'
Effective annual rent escalations (as a percent)	3.00%
Maximum	'
Nature of Business [Line Items]	'
Effective annual rent escalations (as a percent)	3.50%

Background_Schedule_of_rentabl

Background Schedule of rentable square feet (Details)	Jun. 30, 2014
	sqft
Real Estate Properties [Line Items]	'
Area of Real Estate Property	17,881,108
Square Footage of Real Estate Property, Future Development	13,497,221
Total Rentable Square Footage of Asset Base	31,378,329
Operating properties [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	15,804,327
Development [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	1,879,492
Redevelopment [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	197,289
Land undergoing predevelopment activities (CIP) in North America (2)	'
Real Estate Properties [Line Items]	'
Square Footage of Real Estate Property, Future Development	2,474,163
Land held for future development in North America	'
Real Estate Properties [Line Items]	'
Square Footage of Real Estate Property, Future Development	10,760,108
Land subject to sale negotiations	'
Real Estate Properties [Line Items]	'
Square Footage of Real Estate Property, Future Development	262,950

Basis_of_presentation_Details

Basis of presentation (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Basis of presentation	'	'	'	'	'
Maximum expected period of sale of property (in years)	'	'	'1 year	'	'
Cost method investment ownership percentage	10.00%	'	10.00%	'	10.00%
The Company generally distributes this percentage or more of its taxable income	'	'	100.00%	'	'
Minimum percentage of taxable income to be distributed	'	'	100.00%	'	'
Provision for federal income taxes	'	'	$0	'	'
Allowance for estimated losses	'	'	0	'	0
Interest income included in other income	$900,000	$1,000,000	$1,800,000	$2,300,000	'
Maximum	'	'	'	'	'
Basis of presentation	'	'	'	'	'
Percentage of ownership interest criteria	100.00%	'	100.00%	'	'
Land improvements	'	'	'	'	'
Property, plant and equipment depreciated on a straight-line basis using an estimated life	'	'	'	'	'
Estimated useful life	'	'	'20 years	'	'
Buildings and building improvements | Maximum	'	'	'	'	'
Property, plant and equipment depreciated on a straight-line basis using an estimated life	'	'	'	'	'
Estimated useful life	'	'	'40 years	'	'

Investments_in_real_estate_net2

Investments in real estate, net Schedule of investment in real estates (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Real Estate Properties [Line Items]	'	'
Rental properties	$6,668,458	$6,442,208
Less: accumulated depreciation	-1,039,810	-952,106
Rental properties, net	5,628,648	5,490,102
Construction in progress ("CIP")/current value-added projects:	'	'
Investments in real estate, net	7,030,117	6,776,914
Construction in progress ("CIP")/current value-added projects:	'	'
Construction in progress ("CIP")/current value-added projects:	'	'
Development in process	706,187	628,266
Active development in North America | North America [Member]	'	'
Construction in progress ("CIP")/current value-added projects:	'	'
Development in process	613,104	558,482
Active redevelopment in North America | North America [Member]	'	'
Construction in progress ("CIP")/current value-added projects:	'	'
Development in process	32,139	8,856
Active development and redevelopment in Asia | Asia [Member]	'	'
Construction in progress ("CIP")/current value-added projects:	'	'
Development in process	60,944	60,928
Land undergoing predevelopment activities (CIP) in North America (2)	'	'
Land/future value-added projects:	'	'
Land available for development	402,838	382,289
Land held for future development in North America	'	'
Land/future value-added projects:	'	'
Land available for development	284,749	253,314
Land held for future development in North America | North America [Member]	'	'
Land/future value-added projects:	'	'
Land available for development	205,421	176,063
Land held for future development in North America | Asia [Member]	'	'
Land/future value-added projects:	'	'
Land available for development	79,328	77,251
Land subject to sale negotiations	'	'
Land/future value-added projects:	'	'
Land available for development	7,695	22,943
Rental properties, net and Construction in progress ("CIP")/current value-added projects	'	'
Construction in progress ("CIP")/current value-added projects:	'	'
Investments in real estate, net	6,334,835	6,118,368
Other Projects in North America [Member] | Land undergoing predevelopment activities (CIP) in North America (2)	'	'
Land/future value-added projects:	'	'
Land available for development	108,790	97,617
50, 60, and 100 Binney Street Project [Member] | Land undergoing predevelopment activities (CIP) in North America (2)	'	'
Land/future value-added projects:	'	'
Land available for development	$294,048	$284,672

Investments_in_real_estate_net3

Investments in real estate, net Acquisitions (Details) (USD $)	6 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 27, 2014	Jan. 30, 2014	Mar. 17, 2014	Apr. 18, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	sqft		Greater Boston, Massachusetts	San Diego, California	San Diego, California	San Francisco, California	Secured Debt Maturing on January 2023	Secured Debt Maturing On 15 April 2016	Secured Debt Maturing On 15 April 2016
			225 Second Avenue	3545 Cray Court	4025/4031/4045 Sorrento Valley Boulevard	500 Townsend Street	San Diego, California		San Diego, California
			sqft	sqft	property	sqft	3545 Cray Court		4025/4031/4045 Sorrento Valley Boulevard
					sqft
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'	'
Area of Real Estate Property	17,881,108	'	112,500	116,600	42,566	300,000	'	'	'
Payments to acquire real estate property	'	'	$16,300,000	$64,000,000	$12,400,000	$50,000,000	'	'	'
Average percentage of occupied properties	'	'	'	100.00%	100.00%	'	'	'	'
Assumption of secured notes payable in connection with purchase of properties	$48,329,000	$0	'	$40,700,000	$7,600,000	'	'	'	'
Number of real estate properties	'	'	'	'	3	'	'	'	'
Stated interest rate (as a percent)	'	'	'	'	'	'	4.66%	5.74%	5.74%

Investments_in_real_estate_net4

Investments in real estate, net Development and redevelopment projects (Details)	Jun. 30, 2014
	sqft
Real Estate Properties [Line Items]	'
Area of Real Estate Property	17,881,108
Development [Member]	'
Real Estate Properties [Line Items]	'
Number of real estate properties	6
Redevelopment [Member]	'
Real Estate Properties [Line Items]	'
Number of real estate properties	3
North America [Member] | Development [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	1,414,036
North America [Member] | Redevelopment [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	197,289

Investments_in_real_estate_net5

Investments in real estate, net Investment in unconsolidated entity (Details) (USD $)	6 Months Ended
	Jun. 30, 2014
Schedule of Equity Method Investments [Line Items]	'
Area of Real Estate Property	17,881,108
Greater Boston market | Equity Method Investee	'
Schedule of Equity Method Investments [Line Items]	'
Equity interest percentage (in percent)	27.50%
Equity Method Investments	48,048,000
Debt Instrument, Variable Rate Base [Domain] | Greater Boston market | Equity Method Investee	'
Schedule of Equity Method Investments [Line Items]	'
Base rate	'LIBOR
Debt Instrument, Variable Rate Spread [Member] | Greater Boston market | Equity Method Investee	'
Schedule of Equity Method Investments [Line Items]	'
Applicable margin (as a percent)	3.75%
Debt Instrument, Variable Rate Floor [Member] | Greater Boston market | Equity Method Investee	'
Schedule of Equity Method Investments [Line Items]	'
Debt Instrument, Interest Rate Floor	5.25%
Longwood [Member] | Greater Boston market	'
Schedule of Equity Method Investments [Line Items]	'
Expected Total Joint Venture Development Cost	350,000,000
Longwood [Member] | Greater Boston market | Equity Method Investee	'
Schedule of Equity Method Investments [Line Items]	'
Area of Real Estate Property	413,536
Pre-leased RSF as a Percentage of Total RSF	37.00%
Longwood [Member] | Aggregate Commitments [Member] | Greater Boston market	'
Schedule of Equity Method Investments [Line Items]	'
Long-term Construction Loan	213,200,000
Longwood [Member] | Outstanding Balance [Member] | Greater Boston market	'
Schedule of Equity Method Investments [Line Items]	'
Long-term Construction Loan	128,000,000
Longwood [Member] | Remaining Commitments [Member] | Greater Boston market	'
Schedule of Equity Method Investments [Line Items]	'
Long-term Construction Loan	85,200,000

Investments_in_real_estate_net6

Investments in real estate, net Land undergoing predevelopment and future development (Details)	Jun. 30, 2014
	sqft
Real Estate Properties [Line Items]	'
Area of Real Estate Property	17,881,108
Land undergoing predevelopment activities (CIP) in North America (2) | North America [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	2,474,163
Land undergoing predevelopment activities (CIP) in North America (2) | Alexandria Centerâ„¢ at Kendall Square	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	1,100,000
Land held for future development in North America	'
Real Estate Properties [Line Items]	'
Number of construction or preconstruction activities	0
Land held for future development in North America | North America [Member]	'
Real Estate Properties [Line Items]	'
Area of Real Estate Property	3,155,401

Investments_in_real_estate_net7

Investments in real estate, net Dispositions (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Dispositions [Abstract]	'	'	'	'
Proceeds from Sale of Real Estate	'	'	$19,000,000	'
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	$797,000	$772,000	$797,000	$772,000

Investments_Summary_of_Investm

Investments Summary of Investments (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013	Dec. 31, 2013
Investments [Abstract]	'		'	'		'	'
“Available-for-sale” marketable equity securities, cost basis	$12,937,000		'	$12,937,000		'	$2,879,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	19,338,000	[1]	'	19,338,000	[1]	'	2,177,000
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	-1,297,000		'	-1,297,000		'	-587,000
“Available-for-sale” marketable equity securities, at fair value	30,978,000		'	30,978,000		'	4,469,000
Investments accounted for under cost method	143,824,000		'	143,824,000		'	135,819,000
Marketable Securities	174,802,000		'	174,802,000		'	140,288,000
Unrealized holding (losses) gains arising during the period	-2,734,000		44,000	16,045,000		360,000	'
Unrealized Loss in Investment in Privately Held Entities	$0		'	$0		'	$0
[1]	The increase in our investments during the six months ended June 30, 2014, was primarily related to an increase in unrealized gains of approximately $16.0 million related to our investments in publicly traded life science companies. These unrealized gains are a component of our comprehensive income, within our stockholders’ equity, and have not been recognized in the accompanying consolidated statement of income for the six months ended June 30, 2014.

Investments_Investment_Income_

Investments Investment Income (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investments [Abstract]	'	'	'	'
Gain on Sale of Investments	$2,185	$2,220	$6,225	$2,666
Investment losses	-3,546	-143	-5,240	-529
Investment (loss) income	($1,361)	$2,077	$985	$2,137

Secured_and_unsecured_senior_d2

Secured and unsecured senior debt Narratives (Details) (USD $)	Jun. 30, 2014	Jan. 31, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified	Greater Boston market	Alexandria Technology Square	Construction Loans
	Equity Method Investee	Secured Debt from Insurance Company Maturing on 1 April 2014
Debt Instrument [Line Items]	'	'	'
Outstanding Balance	'	$208,700	$123,775
Proceeds from Contributions from Affiliates	'	$20,900	'
Equity interest percentage (in percent)	27.50%	'	'

Secured_and_unsecured_senior_d3

Secured and unsecured senior debt Summary of secured and unsecured debt (Details) (USD $)

6 Months Ended

0 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jul. 18, 2014

Jul. 18, 2014

Jul. 18, 2014

Secured notes payable

Senior Notes [Member]

$1.5 billion unsecured senior line of credit

2016 Unsecured Senior Bank Term Loan

2019 Unsecured Senior Bank Term Loan

Unsecured Senior Notes Due in 2020 and 2029 [Member]

$1.5 billion unsecured senior line of credit

2016 Unsecured Senior Bank Term Loan

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Senior Notes [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

Proceeds from Unsecured Notes Payable

'

'

'

'

'

'

'

$694,000,000

'

'

Repayments of Unsecured Debt

0

150,000,000

'

'

'

'

'

'

569,000,000

125,000,000

Fixed Rate/Hedged Variable Rate

2,413,965,000

'

415,655,000

1,048,310,000

0

350,000,000

600,000,000

'

'

'

Unhedged Variable rate

920,896,000

'

199,896,000

0

571,000,000

150,000,000

0

'

'

'

Total Consolidated

$3,334,861,000

'

$615,551,000

$1,048,310,000

$571,000,000

[1]

$500,000,000

[1]

$600,000,000

'

'

'

Percentage of Total

100.00%

'

'

'

'

'

'

'

'

'

Total consolidated debt, Effective Interest

3.03%

[2]

'

'

'

'

'

'

'

'

'

Weighted Average Interest Rate at End of Period

'

'

4.83%

[2]

4.29%

[2]

1.25%

[2]

1.40%

[2]

2.05%

[2]

'

'

'

Weighted Average Remaining Terms (in years)

'5 years 1 month

'

'3 years 2 months

'8 years 3 months

'4 years 6 months

'2 years 1 month

'4 years 6 months

'9 years 7 months

'

'

Percentage of fixed rate/hedged total debt

72.00%

'

'

'

'

'

'

'

'

'

Percentage of unhedged floating rate total debt

28.00%

'

'

'

'

'

'

'

'

'

[1]

These amounts do not reflect our unsecured senior notes payable offering completed on July 18, 2014. Net proceeds of $694 million were used to reduce variable-rate debt, including the partial repayment of $125 million of our 2016 Unsecured Senior Bank Term Loan and the reduction of $569 million of borrowings outstanding on our unsecured senior line of credit. See Note 13 – Subsequent Events, to our consolidated financial statements (unaudited) appearing elsewhere in this quarterly report on Form 10-Q for further information.

[2]

Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.

Secured_and_unsecured_senior_d4

Secured and unsecured senior debt Detail of secured and unsecured debt (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	$2,413,965		'
Unhedged Variable rate	920,896		'
Principal amount	3,334,861		'
Total consolidated debt, Effective Interest	3.03%	[1]	'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	3,300,992		'
Debt Instrument, Annual Principal Payment	33,869		'
Future principal payments due on secured and unsecured debt	'		'
Repayments of Unsecured Debt	0		150,000
Percentage of unhedged floating rate total debt	28.00%		'
2014	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	11,583		'
Unhedged Variable rate	120		'
Principal amount	11,703		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	7,339		'
Debt Instrument, Annual Principal Payment	4,364		'
2015	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	14,446		'
Unhedged Variable rate	46,399		'
Principal amount	60,845		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	52,139		'
Debt Instrument, Annual Principal Payment	8,706		'
2016	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	591,582		'
Unhedged Variable rate	161,937		'
Principal amount	753,519		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	748,836		'
Debt Instrument, Annual Principal Payment	4,683		'
2017	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	3,208		'
Unhedged Variable rate	141,440		'
Principal amount	144,648		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	141,440		'
Debt Instrument, Annual Principal Payment	3,208		'
2018	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	3,423		'
Unhedged Variable rate	0		'
Principal amount	3,423		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	0		'
Debt Instrument, Annual Principal Payment	3,423		'
Thereafter	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	1,789,723		'
Unhedged Variable rate	571,000		'
Principal amount	2,360,723		'
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	2,351,238		'
Debt Instrument, Annual Principal Payment	9,485		'
Secured notes payable	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	415,655		'
Unhedged Variable rate	199,896		'
Principal amount	615,551		'
Stated interest rate (as a percent)	4.89%		'
Effective rate (as a percent)	4.83%	[1]	'
Future principal payments due on secured and unsecured debt	'		'
2014	11,785		'
2015	61,015		'
2016	253,696		'
2017	144,832		'
2018	3,615		'
Thereafter	140,608		'
Secured notes payable from bank maturing on 11/1/14	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	5.39%		'
Effective rate (as a percent)	4.00%	[1]	'
Maturity Date	1-Nov-14	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	7,386		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	7,386		'
Other secured notes payable maturing on 11/18/14	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	6.00%		'
Effective rate (as a percent)	6.00%	[1]	'
Maturity Date	18-Nov-14	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	120		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	120		'
Secured notes payable from bank maturing on 6/1/15	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	5.64%		'
Effective rate (as a percent)	4.50%	[1]	'
Maturity Date	1-Jun-15	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	69		'
2015	5,777		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	5,846		'
Secured notes payable maturing on 7/1/15	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Effective rate (as a percent)	1.66%	[1]	'
Maturity Date	1-Jul-15	[2]	'
Number of extensions available under line of credit	2		'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	46,399		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	46,399		'
CMBS maturing on 1/1/16	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	5.73%		'
Effective rate (as a percent)	5.73%	[1]	'
Maturity Date	1-Jan-16	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	862		'
2015	1,816		'
2016	75,501		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	78,179		'
CMBS maturing on 4/1/16	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	5.82%		'
Effective rate (as a percent)	5.82%	[1]	'
Maturity Date	1-Apr-16	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	465		'
2015	988		'
2016	29,389		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	30,842		'
Secured Debt Maturing On 15 April 2016	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	5.74%		'
Effective rate (as a percent)	3.00%	[1]	'
Maturity Date	15-Apr-16	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	83		'
2015	175		'
2016	6,916		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	7,174		'
Secured notes payable maturing on 06/1/16	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Effective rate (as a percent)	1.56%	[1]	'
Maturity Date	1-Jun-16	[2]	'
Number of extensions available under line of credit	2		'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	11,936		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	11,936		'
CMBS maturing on 8/1/16	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	6.35%		'
Effective rate (as a percent)	6.35%	[1]	'
Maturity Date	1-Aug-16	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	1,229		'
2015	2,652		'
2016	126,715		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	130,596		'
Secured Debt from Bank Maturing on 20 January 2017	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	2.14%		'
Effective rate (as a percent)	2.14%	[1]	'
Maturity Date	20-Jan-17	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	76,000		'
2018	0		'
Thereafter	0		'
Outstanding Balance	76,000		'
Secured notes payable maturing on 8/23/17	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Effective rate (as a percent)	1.50%	[1]	'
Maturity Date	23-Aug-17	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	65,440		'
2018	0		'
Thereafter	0		'
Outstanding Balance	65,440		'
Secured Debt Other Maturing 1 April 2020	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	7.75%		'
Effective rate (as a percent)	7.75%	[1]	'
Maturity Date	1-Apr-20	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	741		'
2015	1,570		'
2016	1,696		'
2017	1,832		'
2018	1,979		'
Thereafter	106,490		'
Outstanding Balance	114,308		'
Secured Debt Maturing on January 2023	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	4.66%		'
Effective rate (as a percent)	4.66%	[1]	'
Maturity Date	1-Jan-23	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	669		'
2015	1,402		'
2016	1,464		'
2017	1,540		'
2018	1,614		'
Thereafter	33,367		'
Outstanding Balance	40,056		'
Secured notes payable from bank maturing on 6/1/37	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	6.50%		'
Effective rate (as a percent)	6.50%	[1]	'
Maturity Date	1-Jun-37	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	18		'
2016	19		'
2017	20		'
2018	22		'
Thereafter	751		'
Outstanding Balance	830		'
Unamortized Premiums	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	439		'
Unamortized Premiums | 2014	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	161		'
Unamortized Premiums | 2015	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	218		'
Unamortized Premiums | 2016	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	60		'
Unamortized Premiums | 2017	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	0		'
Unamortized Premiums | 2018	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	0		'
Unamortized Premiums | Thereafter	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized premium	0		'
Unsecured Debt	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Principal amount	2,719,310		'
Effective rate (as a percent)	2.63%	[1]	'
Unsecured Debt | 2014	'		'
Future principal payments due on secured and unsecured debt	'		'
2014	-82		'
Unsecured Debt | 2015	'		'
Future principal payments due on secured and unsecured debt	'		'
2015	-170		'
Unsecured Debt | 2016	'		'
Future principal payments due on secured and unsecured debt	'		'
2016	499,823		'
Unsecured Debt | 2017	'		'
Future principal payments due on secured and unsecured debt	'		'
2017	-184		'
Unsecured Debt | 2018	'		'
Future principal payments due on secured and unsecured debt	'		'
2018	-192		'
Unsecured Debt | Thereafter	'		'
Future principal payments due on secured and unsecured debt	'		'
Thereafter	2,220,115		'
2016 Unsecured Senior Bank Term Loan	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	350,000		'
Unhedged Variable rate	150,000		'
Principal amount	500,000	[3]	'
Effective rate (as a percent)	1.40%	[1]	'
Maturity Date	31-Jul-16	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	500,000		'
2017	0		'
2018	0		'
Thereafter	0		'
Outstanding Balance	500,000		'
2019 Unsecured Senior Bank Term Loan	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	600,000		'
Unhedged Variable rate	0		'
Principal amount	600,000		'
Effective rate (as a percent)	2.05%	[1]	'
Maturity Date	3-Jan-19	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	600,000		'
Outstanding Balance	600,000		'
$1.5 billion unsecured senior line of credit	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	0		'
Unhedged Variable rate	571,000		'
Principal amount	571,000	[3]	'
Effective rate (as a percent)	1.25%	[1]	'
Maturity Date	3-Jan-19	[2]	'
Annual facility fee (as a percent)	0.20%		'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	571,000		'
Outstanding Balance	571,000		'
4.60% unsecured senior notes payable	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	4.60%		'
Effective rate (as a percent)	4.61%	[1]	'
Maturity Date	1-Apr-22	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	550,000		'
Outstanding Balance	550,000		'
3.90% unsecured senior notes payable	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Stated interest rate (as a percent)	3.90%		'
Effective rate (as a percent)	3.94%	[1]	'
Maturity Date	15-Jun-23	[2]	'
Future principal payments due on secured and unsecured debt	'		'
2014	0		'
2015	0		'
2016	0		'
2017	0		'
2018	0		'
Thereafter	500,000		'
Outstanding Balance	500,000		'
Unamortized Discounts	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-1,690		'
Unamortized Discounts | 2014	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-82		'
Unamortized Discounts | 2015	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-170		'
Unamortized Discounts | 2016	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-177		'
Unamortized Discounts | 2017	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-184		'
Unamortized Discounts | 2018	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-192		'
Unamortized Discounts | Thereafter	'		'
Future principal payments due on secured and unsecured debt	'		'
Unamortized discount	-885		'
Senior Notes [Member]	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Fixed Rate/Hedged Variable Rate	1,048,310		'
Unhedged Variable rate	0		'
Principal amount	$1,048,310		'
Effective rate (as a percent)	4.29%	[1]	'
LIBOR | Secured notes payable maturing on 7/1/15	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.50%		'
LIBOR | Secured notes payable maturing on 06/1/16	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.40%		'
LIBOR | Secured notes payable maturing on 8/23/17	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.35%		'
LIBOR | 2016 Unsecured Senior Bank Term Loan	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.20%		'
LIBOR | 2019 Unsecured Senior Bank Term Loan	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.20%		'
LIBOR | $1.5 billion unsecured senior line of credit	'		'
Summary of fixed rate/hedged and floating rate debt	'		'
Base rate	'LIBOR		'
Basis spread on LIBOR (as a percent)	1.10%	[4]	'
[1]	Represents the weighted average interest rate as of the end of the period plus the impact of debt premiums/discounts and our interest rate swap agreements. The weighted average interest rate excludes bank fees and amortization of loan fees.
[2]	Includes any extension options that we control.
[3]	These amounts do not reflect our unsecured senior notes payable offering completed on July 18, 2014. Net proceeds of $694 million were used to reduce variable-rate debt, including the partial repayment of $125 million of our 2016 Unsecured Senior Bank Term Loan and the reduction of $569 million of borrowings outstanding on our unsecured senior line of credit. See Note 13 – Subsequent Events, to our consolidated financial statements (unaudited) appearing elsewhere in this quarterly report on Form 10-Q for further information.
[4]	In addition to the stated rate, the unsecured senior line of credit is subject to an annual facility fee of 0.20%.

Secured_and_unsecured_senior_d5

Secured and unsecured senior debt Schedule of interest expense (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Interest expense incurred	'	'	'	'
Gross interest	$28,735	$31,668	$59,871	$63,709
Capitalized interest	-11,302	-15,690	-23,315	-29,711
Interest	$17,433	$15,978	$36,556	$33,998

Secured_and_unsecured_senior_d6

Secured and unsecured senior debt Schedule of secured construction loans (Details) (Construction Loans, USD $)	6 Months Ended
	Jun. 30, 2014
Debt Instrument [Line Items]	'
Outstanding Balance	$123,775,000
Remaining Commitment	217,625,000
Total Aggregate Commitments	341,400,000
San Francisco Bay Area | Secured notes payable maturing on 7/1/15	'
Debt Instrument [Line Items]	'
Maturity Date	1-Jul-15	[1]
Outstanding Balance	46,399,000
Remaining Commitment	8,601,000
Total Aggregate Commitments	55,000,000
San Francisco Bay Area | Secured notes payable maturing on 06/1/16	'
Debt Instrument [Line Items]	'
Maturity Date	1-Jun-16	[2]
Outstanding Balance	11,936,000
Remaining Commitment	24,064,000
Total Aggregate Commitments	36,000,000
Greater Boston market | Secured notes payable maturing on 8/23/17	'
Debt Instrument [Line Items]	'
Maturity Date	23-Aug-17	[3]
Outstanding Balance	65,440,000
Remaining Commitment	184,960,000
Total Aggregate Commitments	$250,400,000
LIBOR | San Francisco Bay Area | Secured notes payable maturing on 7/1/15	'
Debt Instrument [Line Items]	'
Base rate	'LIBOR
Applicable margin (as a percent)	1.50%
LIBOR | San Francisco Bay Area | Secured notes payable maturing on 06/1/16	'
Debt Instrument [Line Items]	'
Base rate	'LIBOR
Applicable margin (as a percent)	1.40%
LIBOR | Greater Boston market | Secured notes payable maturing on 8/23/17	'
Debt Instrument [Line Items]	'
Base rate	'LIBOR
Applicable margin (as a percent)	1.35%
[1]	We have two, one-year options to extend the stated maturity date to July 1, 2017, subject to certain conditions.
[2]	We have two, one-year options to extend the stated maturity date to June 1, 2018, subject to certain conditions.
[3]	We have a one-year option to extend the stated maturity date to August 23, 2018, subject to certain conditions.

Interest_rate_swap_agreements_1

Interest rate swap agreements (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'
The percentage of effectiveness of interest rate swap agreements	100.00%	100.00%
Interest rate swap hedge ineffectiveness recognized in earnings	$0	$0
Cash flow hedge loss to be reclassified within twelve month	3,100,000	'
Collateral obligation requirements	0	'
Interest Rate Derivative Liabilities, at Fair Value	2,600,000	'
Assets Needed for Immediate Settlement, Aggregate Fair Value	$2,600,000	'

Interest_rate_swap_agreements_2

Interest rate swap agreements Outstanding interest rate swap (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014
Interest rate hedge agreements	'
Interest Rate Derivative Liabilities, at Fair Value	2,600
Fair Values	-2,622
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	950,000
Notional Amount in Effect as of 12/31/14	950,000
Notional Amount in Effect as of 12/31/15	500,000
Notional Amount in Effect as of 12/31/16	500,000
Unsecured Bank Term Loan 2016 | Minimum	'
Interest rate hedge agreements	'
Applicable margin (as a percent)	1.20%
Unsecured Credit Facility [Member] | Minimum	'
Interest rate hedge agreements	'
Applicable margin (as a percent)	1.10%
Transaction Date December 2013, Interest Pay Rate .980%	'
Interest rate hedge agreements	'
Number of Contracts	2
Interest Pay Rate (as a percent)	0.98%	[1]
Fair Values	-2,114
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	500,000
Notional Amount in Effect as of 12/31/14	0
Notional Amount in Effect as of 12/31/15	0
Notional Amount in Effect as of 12/31/16	0
Interest Rate Hedge .23 Percent Transaction Date December 2013	'
Interest rate hedge agreements	'
Number of Contracts	2
Interest Pay Rate (as a percent)	0.23%	[1]
Fair Values	-144
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	250,000
Notional Amount in Effect as of 12/31/14	250,000
Notional Amount in Effect as of 12/31/15	0
Notional Amount in Effect as of 12/31/16	0
Interest Rate Hedge .21 Percent Transaction Date March 2014 [Member]	'
Interest rate hedge agreements	'
Number of Contracts	4
Interest Pay Rate (as a percent)	0.21%	[1]
Fair Values	-75
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	200,000
Notional Amount in Effect as of 12/31/14	200,000
Notional Amount in Effect as of 12/31/15	0
Notional Amount in Effect as of 12/31/16	0
Transaction date December 2014, interest pay rate 0.527%	'
Interest rate hedge agreements	'
Number of Contracts	3
Interest Pay Rate (as a percent)	0.53%	[1]
Fair Values	-335
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	0
Notional Amount in Effect as of 12/31/14	500,000
Notional Amount in Effect as of 12/31/15	500,000
Notional Amount in Effect as of 12/31/16	0
Transaction date March 2016, interest pay rate 1.406%	'
Interest rate hedge agreements	'
Number of Contracts	3
Interest Pay Rate (as a percent)	1.40%	[1]
Fair Values	46
Effective Portion of Interest Rate Cash Flow Hedge Derivatives	0
Notional Amount in Effect as of 12/31/14	0
Notional Amount in Effect as of 12/31/15	0
Notional Amount in Effect as of 12/31/16	500,000
[1]	In addition to the interest pay rate, borrowings outstanding as of June 30, 2014, under our unsecured senior bank term loans include an applicable margin of 1.20% and borrowings outstanding under our unsecured senior line of credit include an applicable margin of 1.10%.

Fair_value_measurements_Assets

Fair value measurements Assets and Liabilities on Recurring Basis (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:	'	'
“Available-for-sale” securities	$30,978	$4,469
Liabilities:	'	'
Interest rate swap agreements	2,600	'
Fair value measured on recurring basis | Fair Value	'	'
Assets:	'	'
“Available-for-sale” securities	30,978	4,469
Interest rate swap agreements	46	2,870
Liabilities:	'	'
Interest rate swap agreements	2,668	6,191
Fair value measured on recurring basis | Quoted Prices in Active Markets for Identical Assets	'	'
Assets:	'	'
“Available-for-sale” securities	30,978	4,469
Interest rate swap agreements	0	0
Liabilities:	'	'
Interest rate swap agreements	0	0
Fair value measured on recurring basis | Significant Other Observable Inputs	'	'
Assets:	'	'
“Available-for-sale” securities	0	0
Interest rate swap agreements	46	2,870
Liabilities:	'	'
Interest rate swap agreements	2,668	6,191
Fair value measured on recurring basis | Significant Other Observable Inputs	'	'
Assets:	'	'
“Available-for-sale” securities	0	0
Interest rate swap agreements	0	0
Liabilities:	'	'
Interest rate swap agreements	$0	$0

Fair_value_measurements_Book_a

Fair value measurements Book and Fair Values (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
“Available-for-sale” securities	$30,978	$4,469
Interest rate swap agreements	2,600	'
Book Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
“Available-for-sale” securities	30,978	4,469
Interest rate swap agreements	46	2,870
Interest rate swap agreements	2,668	6,191
Secured notes payable	615,551	708,831
Unsecured senior line of credit	571,000	204,000
Fair Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
“Available-for-sale” securities	30,978	4,469
Interest rate swap agreements	46	2,870
Interest rate swap agreements	2,668	6,191
Secured notes payable	664,724	736,772
Unsecured senior line of credit	570,393	193,714
Senior Notes [Member] | Book Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
Debt Instrument, Fair Value Disclosure	1,048,310	1,048,230
Senior Notes [Member] | Fair Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
Debt Instrument, Fair Value Disclosure	1,081,305	1,043,125
Unsecured Bank Term Loan 2016 | Book Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
Debt Instrument, Fair Value Disclosure	1,100,000	1,100,000
Unsecured Bank Term Loan 2016 | Fair Value	'	'
Summary of marketable securities, secured notes payable, unsecured senior line of credit, unsecured term loans, and unsecured senior convertible notes	'	'
Debt Instrument, Fair Value Disclosure	$1,099,326	$1,099,897

Earnings_per_share_Details

Earnings per share (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Earnings per share	'		'		'		'
Income from continuing operations	$35,466		$32,316		$76,377		$61,716
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	797		772		797		772
Dividends on preferred stock	-6,472		-6,471		-12,943		-12,942
Net income attributable to noncontrolling interests	-1,307		-980		-2,502		-1,962
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	-405		-403		-779		-745
Income from continuing operations attributable to Alexandria Real Estate Equities, Inc.'s common stockholders - basic and diluted	28,079		25,234		60,950		46,839
(Loss) income from discontinued operations, net	-147	[1]	249	[1]	-309	[1]	1,086	[1]
Net income attributable to Alexandria’s common stockholders	$27,932		$25,483		$60,641		$47,925
Weighted average shares of common stock outstanding – basic and diluted	71,126		66,973		71,100		65,078
Earnings per share attributable to Alexandria Real Estate Equities, Inc.'s common stockholders - basic and diluted:	'		'		'		'
Continuing operations	$0.39		$0.38		$0.85		$0.72
Discontinued operations	$0		$0		$0		$0.02
Earnings per share – basic and diluted	$0.39		$0.38		$0.85		$0.74
[1]	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Net_income_attributable_to_Ale2

Net income attributable to Alexandria Real Estate Equities, Inc. (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Net income attributable to Alexandria Real Estate Equities, Inc.:	'		'		'		'
Income from continuing operations	$35,466		$32,316		$76,377		$61,716
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	797		772		797		772
Net income attributable to noncontrolling interests	-1,307		-980		-2,502		-1,962
Income from continuing operations attributable to Alexandria Real Estate Equities, Inc.	34,956		32,108		74,672		60,526
(Loss) income from discontinued operations	-147	[1]	249	[1]	-309	[1]	1,086	[1]
Net income attributable to Alexandria Real Estate Equities, Inc.	$34,809		$32,357		$74,363		$61,612
[1]	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Stockholders_equity_Details

Stockholders' equity (Details) (USD $)	3 Months Ended	6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014
Issuances of common stock	'	'
Dividends declared on common stock	$51,700	$101,824
Dividends declared on common stock (dollar per share)	$0.72	'
Dividends declared on preferred stock	'	12,943
Preferred stock, shares authorized	100,000,000	100,000,000
Number of shares issued and outstanding	15,200,000	15,200,000
Number of "excess stock" authorized (in shares)	'	200,000,000
Number of excess stock authorized issued and outstanding (in shares)	0	0
Series D Preferred Stock	'	'
Issuances of common stock	'	'
Dividends declared on preferred stock	4,400	'
Dividends declared on preferred stock (dollar per share)	$0.44	'
Series E Cumulative Redeemable Preferred Stock	'	'
Issuances of common stock	'	'
Dividends declared on preferred stock	$2,100	'
Dividends declared on preferred stock (dollar per share)	$0.40	'

Stockholders_equity_Accumulate

Stockholders' equity Accumulated other comprehensive loss (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014
Increase (Decrease) Accumulated Other Comprehensive Income (Loss) Net of Tax [Roll Forward]	'
Balance as of December 31, 2013	($36,204)
Other comprehensive income before reclassifications	14,940
Amounts reclassified from other comprehensive income	5,019
Net other comprehensive income	19,959
Balance as of June 30, 2014	-16,245
Unrealized Gain on Marketable Securities	'
Increase (Decrease) Accumulated Other Comprehensive Income (Loss) Net of Tax [Roll Forward]	'
Balance as of December 31, 2013	1,590
Other comprehensive income before reclassifications	16,045
Amounts reclassified from other comprehensive income	406
Net other comprehensive income	16,451
Balance as of June 30, 2014	18,041
Unrealized Loss on Interest Rate Swap Agreements	'
Increase (Decrease) Accumulated Other Comprehensive Income (Loss) Net of Tax [Roll Forward]	'
Balance as of December 31, 2013	-3,321
Other comprehensive income before reclassifications	-3,914
Amounts reclassified from other comprehensive income	4,613
Net other comprehensive income	699
Balance as of June 30, 2014	-2,622
Unrealized Loss on Foreign Currency Translation	'
Increase (Decrease) Accumulated Other Comprehensive Income (Loss) Net of Tax [Roll Forward]	'
Balance as of December 31, 2013	-34,473
Other comprehensive income before reclassifications	2,809
Amounts reclassified from other comprehensive income	0
Net other comprehensive income	2,809
Balance as of June 30, 2014	($31,664)

Noncontrolling_interests_Detai

Noncontrolling interests (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Noncontrolling interests	'	'
Redeemable noncontrolling interest balances	$14,381	$14,444
Remaining noncontrolling interests	67,700	47,708
Noncontrolling Interests	'	'
Noncontrolling interests	'	'
Number of properties owned	10	'
Number of development parcels owned	3	'
Remaining noncontrolling interests	67,700	47,708
Redeemable Noncontrolling Interests	'	'
Noncontrolling interests	'	'
Redeemable noncontrolling interest balances	$14,381	$14,444

Discontinued_operations_Detail

Discontinued operations (Details) (USD $)	3 Months Ended				6 Months Ended				18 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014	Dec. 31, 2013
					property				property
Discontinued Operations and Disposal Groups [Abstract]	'		'		'		'		'	'
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	$7,651		'		$7,651		'		$7,651	$7,644
Net assets of discontinued operations	'		'		'		'		'	'
Other assets	35		'		35		'		35	103
Total assets	7,686		'		7,686		'		7,686	7,747
Total liabilities	-135		'		-135		'		-135	-266
Net assets of discontinued operations	7,551		'		7,551		'		7,551	7,481
Income from discontinued operations, net	'		'		'		'		'	'
Total revenues	0		546		0		4,339		'	'
Operating expenses	147		280		309		1,730		'	'
Total revenues less operating expenses from discontinued operations	-147		266		-309		2,609		'	'
Depreciation and Amortization, Discontinued Operations	0		236		0		1,402		'	'
(Gain) loss on sale of real estate	0		-219		0		121		'	'
(Loss) income from discontinued operations	($147)	[1]	$249	[1]	($309)	[1]	$1,086	[1]	'	'
Number of operating properties classified as held for sale	'		'		4		'		'	'
Number of properties sold	'		'		'		'		7	'
[1]	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Subsequent_events_Narrative_De

Subsequent events Narrative (Details) (USD $)

3 Months Ended

6 Months Ended

0 Months Ended

6 Months Ended

0 Months Ended

0 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jul. 18, 2014

Jul. 15, 2014

Jun. 30, 2014

Jul. 18, 2014

Jul. 18, 2014

Jul. 18, 2014

Jul. 18, 2014

Jul. 18, 2014

Jul. 18, 2014

Subsequent Event [Member]

Subsequent Event [Member]

Senior Notes [Member]

Unsecured Senior Notes Due in 2020 and 2029 [Member]

Unsecured Senior Notes Due in 2020 and 2029 [Member]

Unsecured Senior Notes Due in January 2020 [Member]

Unsecured Senior Notes Due in July 2029 [Member]

2016 Unsecured Senior Bank Term Loan

Unsecured Credit Facility [Member]

Parcel

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

'

'

'

'

'

'

$700,000,000

$400,000,000

$300,000,000

'

'

Stated interest rate (as a percent)

'

'

'

'

'

'

'

'

3.50%

2.75%

4.50%

'

'

Weighted Average Remaining Terms (in years)

'

'

'5 years 1 month

'

'

'

'8 years 3 months

'9 years 7 months

'

'

'

'

'

Proceeds from Unsecured Notes Payable

'

'

'

'

'

'

'

694,000,000

'

'

'

'

'

Repayments of Unsecured Debt

'

'

0

150,000,000

'

'

'

'

'

'

'

125,000,000

569,000,000

Gains (Losses) on Extinguishment of Debt

0

560,000

0

560,000

500,000

'

'

'

'

'

'

'

'

Number of Real Estate Properties Sold

'

'

'

'

'

2

'

'

'

'

'

'

'

Proceeds from Sale of Real Estate

'

'

19,000,000

'

'

7,900,000

'

'

'

'

'

'

'

Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes

$797,000

$772,000

$797,000

$772,000

'

$207,000

'

'

'

'

'

'

'

Condensed_consolidating_financ2

Condensed consolidating financial information Balance Sheet (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Assets	'	'	'	'
Investments in real estate, net	$7,030,117	$6,776,914	'	'
Cash and cash equivalents	61,701	57,696	302,205	140,971
Restricted cash	24,519	27,709	'	'
Tenant receivables	10,654	9,918	'	'
Deferred rent	214,793	190,425	'	'
Deferred leasing and financing costs, net	193,621	192,658	'	'
Marketable Securities	174,802	140,288	'	'
Investments in and advances to affiliates	0	0	'	'
Other assets	105,442	134,156	'	'
Total assets	7,815,649	7,529,764	'	'
Liabilities, Noncontrolling Interests, and Equity	'	'	'	'
Secured notes payable	615,551	708,831	'	'
Unsecured senior notes payable	1,048,310	1,048,230	'	'
Unsecured senior line of credit	571,000	204,000	'	'
Loans Payable to Bank	1,100,000	1,100,000	'	'
Accounts Payable and Accrued Liabilities	434,528	435,342	'	'
Dividends payable	57,377	54,420	'	'
Total liabilities	3,826,766	3,550,823	'	'
Redeemable noncontrolling interests	14,381	14,444	'	'
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,906,802	3,916,789	'	'
Noncontrolling interests	67,700	47,708	'	'
Total equity	3,974,502	3,964,497	'	'
Total liabilities, noncontrolling interests, and equity	7,815,649	7,529,764	'	'
Alexandria Real Estate Equities, Inc. (Issuer)	'	'	'	'
Assets	'	'	'	'
Investments in real estate, net	0	0	'	'
Cash and cash equivalents	18,041	14,790	256,299	98,567
Restricted cash	64	55	'	'
Tenant receivables	0	0	'	'
Deferred rent	0	0	'	'
Deferred leasing and financing costs, net	33,298	36,901	'	'
Marketable Securities	0	0	'	'
Investments in and advances to affiliates	6,678,756	6,299,551	'	'
Other assets	18,740	20,226	'	'
Total assets	6,748,899	6,371,523	'	'
Liabilities, Noncontrolling Interests, and Equity	'	'	'	'
Secured notes payable	0	0	'	'
Unsecured senior notes payable	1,048,310	1,048,230	'	'
Unsecured senior line of credit	571,000	204,000	'	'
Loans Payable to Bank	1,100,000	1,100,000	'	'
Accounts Payable and Accrued Liabilities	65,700	48,373	'	'
Dividends payable	57,087	54,131	'	'
Total liabilities	2,842,097	2,454,734	'	'
Redeemable noncontrolling interests	0	0	'	'
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,906,802	3,916,789	'	'
Noncontrolling interests	0	0	'	'
Total equity	3,906,802	3,916,789	'	'
Total liabilities, noncontrolling interests, and equity	6,748,899	6,371,523	'	'
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)	'	'	'	'
Assets	'	'	'	'
Investments in real estate, net	0	0	'	'
Cash and cash equivalents	0	0	0	1,913
Restricted cash	0	0	'	'
Tenant receivables	0	0	'	'
Deferred rent	0	0	'	'
Deferred leasing and financing costs, net	0	0	'	'
Marketable Securities	9,637	10,868	'	'
Investments in and advances to affiliates	6,162,162	5,823,058	'	'
Other assets	0	0	'	'
Total assets	6,171,799	5,833,926	'	'
Liabilities, Noncontrolling Interests, and Equity	'	'	'	'
Secured notes payable	0	0	'	'
Unsecured senior notes payable	0	0	'	'
Unsecured senior line of credit	0	0	'	'
Loans Payable to Bank	0	0	'	'
Accounts Payable and Accrued Liabilities	0	0	'	'
Dividends payable	0	0	'	'
Total liabilities	0	0	'	'
Redeemable noncontrolling interests	0	0	'	'
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	6,171,799	5,833,926	'	'
Noncontrolling interests	0	0	'	'
Total equity	6,171,799	5,833,926	'	'
Total liabilities, noncontrolling interests, and equity	6,171,799	5,833,926	'	'
Combined Non- Guarantor Subsidiaries	'	'	'	'
Assets	'	'	'	'
Investments in real estate, net	7,030,117	6,776,914	'	'
Cash and cash equivalents	43,660	42,906	45,906	40,491
Restricted cash	24,455	27,654	'	'
Tenant receivables	10,654	9,918	'	'
Deferred rent	214,793	190,425	'	'
Deferred leasing and financing costs, net	160,323	155,757	'	'
Marketable Securities	165,165	129,420	'	'
Investments in and advances to affiliates	125,591	119,421	'	'
Other assets	86,702	113,930	'	'
Total assets	7,861,460	7,566,345	'	'
Liabilities, Noncontrolling Interests, and Equity	'	'	'	'
Secured notes payable	615,551	708,831	'	'
Unsecured senior notes payable	0	0	'	'
Unsecured senior line of credit	0	0	'	'
Loans Payable to Bank	0	0	'	'
Accounts Payable and Accrued Liabilities	368,828	386,969	'	'
Dividends payable	290	289	'	'
Total liabilities	984,669	1,096,089	'	'
Redeemable noncontrolling interests	14,381	14,444	'	'
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	6,794,710	6,408,104	'	'
Noncontrolling interests	67,700	47,708	'	'
Total equity	6,862,410	6,455,812	'	'
Total liabilities, noncontrolling interests, and equity	7,861,460	7,566,345	'	'
Eliminations	'	'	'	'
Assets	'	'	'	'
Investments in real estate, net	0	0	'	'
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0	'	'
Tenant receivables	0	0	'	'
Deferred rent	0	0	'	'
Deferred leasing and financing costs, net	0	0	'	'
Marketable Securities	0	0	'	'
Investments in and advances to affiliates	-12,966,509	-12,242,030	'	'
Other assets	0	0	'	'
Total assets	-12,966,509	-12,242,030	'	'
Liabilities, Noncontrolling Interests, and Equity	'	'	'	'
Secured notes payable	0	0	'	'
Unsecured senior notes payable	0	0	'	'
Unsecured senior line of credit	0	0	'	'
Loans Payable to Bank	0	0	'	'
Accounts Payable and Accrued Liabilities	0	0	'	'
Dividends payable	0	0	'	'
Total liabilities	0	0	'	'
Redeemable noncontrolling interests	0	0	'	'
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	-12,966,509	-12,242,030	'	'
Noncontrolling interests	0	0	'	'
Total equity	-12,966,509	-12,242,030	'	'
Total liabilities, noncontrolling interests, and equity	($12,966,509)	($12,242,030)	'	'

Condensed_consolidating_financ3

Condensed consolidating financial information Income Statement (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Revenues:	'		'		'		'
Rental	$134,992		$114,493		$265,562		$226,019
Tenant recoveries	40,944		35,869		82,626		71,434
Other Income	466		3,568		4,400		6,560
Total revenues	176,402		153,930		352,588		304,013
Expenses:	'		'		'		'
Rental operations	52,353		46,277		104,860		91,463
General and administrative	13,836		12,455		27,060		24,103
Interest	17,433		15,978		36,556		33,998
Depreciation and amortization	57,314		46,344		107,735		92,173
Gains (Losses) on Extinguishment of Debt	0		560		0		560
Total expenses	140,936		121,614		276,211		242,297
(Loss) income from continuing operations before equity in earnings of affiliates	35,466		32,316		76,377		61,716
Income (Loss) from Subsidiaries, before Tax	0		0		0		0
Income from continuing operations	35,466		32,316		76,377		61,716
(Loss) income from discontinued operations	-147	[1]	249	[1]	-309	[1]	1,086	[1]
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	797		772		797		772
Net income	36,116		33,337		76,865		63,574
Dividends on preferred stock	-6,472		-6,471		-12,943		-12,942
Net income attributable to noncontrolling interests	-1,307		-980		-2,502		-1,962
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	-405		-403		-779		-745
Net Income (Loss) Available to Common Stockholders, Basic	27,932		25,483		60,641		47,925
Alexandria Real Estate Equities, Inc. (Issuer)	'		'		'		'
Revenues:	'		'		'		'
Rental	0		0		0		0
Tenant recoveries	0		0		0		0
Other Income	2,916		2,674		5,835		5,269
Total revenues	2,916		2,674		5,835		5,269
Expenses:	'		'		'		'
Rental operations	0		0		0		0
General and administrative	11,506		12,164		22,366		22,433
Interest	12,493		10,090		26,032		21,810
Depreciation and amortization	1,456		1,446		2,927		2,921
Gains (Losses) on Extinguishment of Debt	'		560		'		560
Total expenses	25,455		24,260		51,325		47,724
(Loss) income from continuing operations before equity in earnings of affiliates	-22,539		-21,586		-45,490		-42,455
Income (Loss) from Subsidiaries, before Tax	57,355		53,912		119,860		103,719
Income from continuing operations	34,816		32,326		74,370		61,264
(Loss) income from discontinued operations	-7		31		-7		348
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0		0		0		0
Net income	34,809		32,357		74,363		61,612
Dividends on preferred stock	-6,472		-6,471		-12,943		-12,942
Net income attributable to noncontrolling interests	0		0		0		0
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	-405		-403		-779		-745
Net Income (Loss) Available to Common Stockholders, Basic	27,932		25,483		60,641		47,925
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)	'		'		'		'
Revenues:	'		'		'		'
Rental	0		0		0		0
Tenant recoveries	0		0		0		0
Other Income	-1,535		-75		-1,535		-141
Total revenues	-1,535		-75		-1,535		-141
Expenses:	'		'		'		'
Rental operations	0		0		0		0
General and administrative	0		0		0		0
Interest	0		0		0		0
Depreciation and amortization	0		0		0		0
Gains (Losses) on Extinguishment of Debt	'		0		'		0
Total expenses	0		0		0		0
(Loss) income from continuing operations before equity in earnings of affiliates	-1,535		-75		-1,535		-141
Income (Loss) from Subsidiaries, before Tax	56,302		48,944		114,608		96,183
Income from continuing operations	54,767		48,869		113,073		96,042
(Loss) income from discontinued operations	0		0		0		0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0		0		0		0
Net income	54,767		48,869		113,073		96,042
Dividends on preferred stock	0		0		0		0
Net income attributable to noncontrolling interests	0		0		0		0
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	0		0		0		0
Net Income (Loss) Available to Common Stockholders, Basic	54,767		48,869		113,073		96,042
Combined Non- Guarantor Subsidiaries	'		'		'		'
Revenues:	'		'		'		'
Rental	134,992		114,493		265,562		226,019
Tenant recoveries	40,944		35,869		82,626		71,434
Other Income	2,532		4,098		7,165		7,669
Total revenues	178,468		154,460		355,353		305,122
Expenses:	'		'		'		'
Rental operations	52,353		46,277		104,860		91,463
General and administrative	5,777		3,420		11,759		7,907
Interest	4,940		5,888		10,524		12,188
Depreciation and amortization	55,858		44,898		104,808		89,252
Gains (Losses) on Extinguishment of Debt	'		0		'		0
Total expenses	118,928		100,483		231,951		200,810
(Loss) income from continuing operations before equity in earnings of affiliates	59,540		53,977		123,402		104,312
Income (Loss) from Subsidiaries, before Tax	1,081		939		2,229		1,899
Income from continuing operations	60,621		54,916		125,631		106,211
(Loss) income from discontinued operations	-140		218		-302		738
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	797		772		797		772
Net income	61,278		55,906		126,126		107,721
Dividends on preferred stock	0		0		0		0
Net income attributable to noncontrolling interests	-1,307		-980		-2,502		-1,962
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	0		0		0		0
Net Income (Loss) Available to Common Stockholders, Basic	59,971		54,926		123,624		105,759
Eliminations	'		'		'		'
Revenues:	'		'		'		'
Rental	0		0		0		0
Tenant recoveries	0		0		0		0
Other Income	-3,447		-3,129		-7,065		-6,237
Total revenues	-3,447		-3,129		-7,065		-6,237
Expenses:	'		'		'		'
Rental operations	0		0		0		0
General and administrative	-3,447		-3,129		-7,065		-6,237
Interest	0		0		0		0
Depreciation and amortization	0		0		0		0
Gains (Losses) on Extinguishment of Debt	'		0		'		0
Total expenses	-3,447		-3,129		-7,065		-6,237
(Loss) income from continuing operations before equity in earnings of affiliates	0		0		0		0
Income (Loss) from Subsidiaries, before Tax	-114,738		-103,795		-236,697		-201,801
Income from continuing operations	-114,738		-103,795		-236,697		-201,801
(Loss) income from discontinued operations	0		0		0		0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0		0		0		0
Net income	-114,738		-103,795		-236,697		-201,801
Dividends on preferred stock	0		0		0		0
Net income attributable to noncontrolling interests	0		0		0		0
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	0		0		0		0
Net Income (Loss) Available to Common Stockholders, Basic	($114,738)		($103,795)		($236,697)		($201,801)
[1]	(Loss) income from discontinued operations includes the results of operations of four properties that were classified as “held for sale” as of June 30, 2014, as well as the results of operations (prior to disposition) and (gain) loss on sale of real estate attributable to seven properties sold during the period from January 1, 2013, to June 30, 2014.

Condensed_consolidating_financ4

Condensed consolidating financial information Comprehensive Income (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income	$36,116	$33,337	$76,865	$63,574
Unrealized gains (losses) on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	-2,734	44	16,045	360
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	406	42	406	-230
Unrealized gains on marketable securities, net	-2,328	86	16,451	130
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap losses arising during the period	-2,526	105	-3,914	-28
Reclassification adjustment for amortization of interest expense included in net income	1,123	3,834	4,613	8,142
Unrealized gains on interest rate swap agreements, net	-1,403	3,939	699	8,114
Foreign currency translation losses	5,915	-20,698	2,809	-23,057
Total other comprehensive income (loss)	2,184	-16,673	19,959	-14,813
Comprehensive income	38,300	16,664	96,824	48,761
Less: comprehensive income attributable to noncontrolling interests	-1,307	-1,008	-2,502	-1,906
Comprehensive income attributable to Alexandria’s common stockholders	36,993	15,656	94,322	46,855
Alexandria Real Estate Equities, Inc. (Issuer)	'	'	'	'
Net income	34,809	32,357	74,363	61,612
Unrealized gains (losses) on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	0	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	0	0	0
Unrealized gains on marketable securities, net	0	0	0	0
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap losses arising during the period	-2,526	105	-3,914	-28
Reclassification adjustment for amortization of interest expense included in net income	1,123	3,834	4,613	8,142
Unrealized gains on interest rate swap agreements, net	-1,403	3,939	699	8,114
Foreign currency translation losses	0	0	0	0
Total other comprehensive income (loss)	-1,403	3,939	699	8,114
Comprehensive income	33,406	36,296	75,062	69,726
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Alexandria’s common stockholders	33,406	36,296	75,062	69,726
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)	'	'	'	'
Net income	54,767	48,869	113,073	96,042
Unrealized gains (losses) on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	310	-244	310	405
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	106	0	-375
Unrealized gains on marketable securities, net	310	-138	310	30
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Foreign currency translation losses	0	0	0	0
Total other comprehensive income (loss)	310	-138	310	30
Comprehensive income	55,077	48,731	113,383	96,072
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Alexandria’s common stockholders	55,077	48,731	113,383	96,072
Combined Non- Guarantor Subsidiaries	'	'	'	'
Net income	61,278	55,906	126,126	107,721
Unrealized gains (losses) on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	-3,044	288	15,735	-45
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	406	-64	406	145
Unrealized gains on marketable securities, net	-2,638	224	16,141	100
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Foreign currency translation losses	5,915	-20,698	2,809	-23,057
Total other comprehensive income (loss)	3,277	-20,474	18,950	-22,957
Comprehensive income	64,555	35,432	145,076	84,764
Less: comprehensive income attributable to noncontrolling interests	-1,307	-1,008	-2,502	-1,906
Comprehensive income attributable to Alexandria’s common stockholders	63,248	34,424	142,574	82,858
Eliminations	'	'	'	'
Net income	-114,738	-103,795	-236,697	-201,801
Unrealized gains (losses) on marketable securities:	'	'	'	'
Unrealized holding (losses) gains arising during the period	0	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	0	0	0
Unrealized gains on marketable securities, net	0	0	0	0
Unrealized (losses) gains on interest rate swap agreements:	'	'	'	'
Unrealized interest rate swap losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Foreign currency translation losses	0	0	0	0
Total other comprehensive income (loss)	0	0	0	0
Comprehensive income	-114,738	-103,795	-236,697	-201,801
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Alexandria’s common stockholders	($114,738)	($103,795)	($236,697)	($201,801)

Condensed_consolidating_financ5

Condensed consolidating financial information Cash Flows (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating Activities	'	'	'	'
Net income	$36,116	$33,337	$76,865	$63,574
Depreciation, Depletion and Amortization	'	'	107,735	93,575
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Gains (Losses) on Extinguishment of Debt	0	560	0	560
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	-797	-772	-797	-772
Loss on sale of real estate	0	-219	0	121
Amortization of loan fees and costs	'	'	5,304	4,813
Amortization of debt premiums/discounts	'	'	136	237
Amortization of above and below Market Leases	'	'	-1,434	-1,660
Deferred rent	'	'	-24,619	-14,437
Stock compensation expense	'	'	6,304	7,812
Equity in income related to subsidiaries	'	'	0	0
Investment gains	-2,185	-2,220	-6,225	-2,666
Investment losses	3,546	143	5,240	529
Changes in operating assets and liabilities:	'	'	'	'
Restricted cash	'	'	0	392
Tenant receivables	'	'	-735	847
Deferred leasing costs	'	'	-17,452	-23,109
Other assets	'	'	-5,916	6,110
Intercompany receivables and payables	'	'	'	0
Accounts payable, accrued expenses, and tenant security deposits	'	'	85	8,215
Net cash (used in) provided by operating activities	'	'	144,491	144,141
Investing Activities	'	'	'	'
Proceeds from sale of properties	'	'	17,868	101,815
Additions to properties	'	'	-210,792	-298,927
Purchase of properties	'	'	-97,785	0
Change in restricted cash related to construction projects	'	'	5,650	-8,889
Contributions to unconsolidated real estate entity	'	'	-1,405	-4,889
Gain (Loss) on Investments	'	'	0	-293
Investments in subsidiaries	'	'	0	0
Additions to investments	'	'	-25,358	-14,833
Proceeds from investments	'	'	8,794	9,544
Proceeds from Collection of Notes Receivable	'	'	29,851	0
Net cash (used in) provided by investing activities	'	'	-273,177	-216,472
Financing Activities	'	'	'	'
Borrowings from secured notes payable	'	'	77,762	26,114
Repayments of borrowings from secured notes payable	'	'	-219,427	-31,436
Proceeds from Issuance of Unsecured Debt	'	'	0	495,310
Principal borrowings from unsecured senior line of credit	'	'	637,000	305,000
Repayments of borrowings from unsecured senior line of credit	'	'	-270,000	-871,000
Repayments of Unsecured Debt	'	'	0	-150,000
Transfers to/from parent company	'	'	0	0
Change in restricted cash related to financings	'	'	1,212	16,634
Deferred financing costs paid	'	'	-310	-1,457
Proceeds from Issuance of Common Stock	'	'	0	534,469
Dividends paid on common stock	'	'	-98,867	-73,932
Dividends paid on preferred stock	'	'	-12,943	-12,942
Proceeds from Noncontrolling Interests	'	'	19,410	0
Payments of Distributions to Affiliates	'	'	-595	-596
Distributions to noncontrolling interests	'	'	-1,388	-639
Net cash provided by (used in) financing activities	'	'	131,854	235,525
Effect of foreign exchange rate changes on cash and cash equivalents	'	'	837	-1,960
Net increase in cash and cash equivalents	'	'	4,005	161,234
Cash and cash equivalents at beginning of period	'	'	57,696	140,971
Cash and cash equivalents at end of period	61,701	302,205	61,701	302,205
Supplemental Disclosure of Cash Flow Information	'	'	'	'
Cash paid during the period for interest, net of interest capitalized	'	'	31,922	29,259
Non-Cash Investing Activities	'	'	'	'
Note receivable from sale of real estate	'	'	0	38,820
Change in accrued capital expenditures	'	'	592	-48,198
Assumption of secured notes payable in connection with purchase of properties	'	'	-48,329	0
Alexandria Real Estate Equities, Inc. (Issuer)	'	'	'	'
Operating Activities	'	'	'	'
Net income	34,809	32,357	74,363	61,612
Depreciation, Depletion and Amortization	'	'	2,927	2,921
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Gains (Losses) on Extinguishment of Debt	'	560	'	560
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0	0	0	0
Loss on sale of real estate	'	'	'	0
Amortization of loan fees and costs	'	'	3,542	3,381
Amortization of debt premiums/discounts	'	'	80	31
Amortization of above and below Market Leases	'	'	0	0
Deferred rent	'	'	0	0
Stock compensation expense	'	'	6,304	7,812
Equity in income related to subsidiaries	'	'	-119,860	-103,719
Investment gains	'	'	0	0
Investment losses	'	'	0	0
Changes in operating assets and liabilities:	'	'	'	'
Restricted cash	'	'	-9	10
Tenant receivables	'	'	0	1
Deferred leasing costs	'	'	0	-792
Other assets	'	'	-4,264	31,434
Intercompany receivables and payables	'	'	'	-40
Accounts payable, accrued expenses, and tenant security deposits	'	'	20,850	-20,871
Net cash (used in) provided by operating activities	'	'	-16,067	-17,660
Investing Activities	'	'	'	'
Proceeds from sale of properties	'	'	0	10,796
Additions to properties	'	'	0	0
Purchase of properties	'	'	0	'
Change in restricted cash related to construction projects	'	'	0	0
Contributions to unconsolidated real estate entity	'	'	0	0
Gain (Loss) on Investments	'	'	'	0
Investments in subsidiaries	'	'	-235,931	-61,214
Additions to investments	'	'	0	0
Proceeds from investments	'	'	0	0
Proceeds from Collection of Notes Receivable	'	'	0	'
Net cash (used in) provided by investing activities	'	'	-235,931	-50,418
Financing Activities	'	'	'	'
Borrowings from secured notes payable	'	'	0	0
Repayments of borrowings from secured notes payable	'	'	0	0
Proceeds from Issuance of Unsecured Debt	'	'	'	495,310
Principal borrowings from unsecured senior line of credit	'	'	637,000	305,000
Repayments of borrowings from unsecured senior line of credit	'	'	-270,000	-871,000
Repayments of Unsecured Debt	'	'	'	-150,000
Transfers to/from parent company	'	'	103	0
Change in restricted cash related to financings	'	'	0	0
Deferred financing costs paid	'	'	-44	-1,095
Proceeds from Issuance of Common Stock	'	'	'	534,469
Dividends paid on common stock	'	'	-98,867	-73,932
Dividends paid on preferred stock	'	'	-12,943	-12,942
Proceeds from Noncontrolling Interests	'	'	0	'
Payments of Distributions to Affiliates	'	'	0	0
Distributions to noncontrolling interests	'	'	0	0
Net cash provided by (used in) financing activities	'	'	255,249	225,810
Effect of foreign exchange rate changes on cash and cash equivalents	'	'	0	0
Net increase in cash and cash equivalents	'	'	3,251	157,732
Cash and cash equivalents at beginning of period	'	'	14,790	98,567
Cash and cash equivalents at end of period	18,041	256,299	18,041	256,299
Supplemental Disclosure of Cash Flow Information	'	'	'	'
Cash paid during the period for interest, net of interest capitalized	'	'	22,218	17,969
Non-Cash Investing Activities	'	'	'	'
Note receivable from sale of real estate	'	'	'	29,820
Change in accrued capital expenditures	'	'	0	0
Assumption of secured notes payable in connection with purchase of properties	'	'	0	'
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)	'	'	'	'
Operating Activities	'	'	'	'
Net income	54,767	48,869	113,073	96,042
Depreciation, Depletion and Amortization	'	'	0	0
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Gains (Losses) on Extinguishment of Debt	'	0	'	0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0	0	0	0
Loss on sale of real estate	'	'	'	0
Amortization of loan fees and costs	'	'	0	0
Amortization of debt premiums/discounts	'	'	0	0
Amortization of above and below Market Leases	'	'	0	0
Deferred rent	'	'	0	0
Stock compensation expense	'	'	0	0
Equity in income related to subsidiaries	'	'	-114,608	-96,183
Investment gains	'	'	0	-152
Investment losses	'	'	1,535	297
Changes in operating assets and liabilities:	'	'	'	'
Restricted cash	'	'	0	0
Tenant receivables	'	'	0	0
Deferred leasing costs	'	'	0	0
Other assets	'	'	0	0
Intercompany receivables and payables	'	'	'	0
Accounts payable, accrued expenses, and tenant security deposits	'	'	0	0
Net cash (used in) provided by operating activities	'	'	0	4
Investing Activities	'	'	'	'
Proceeds from sale of properties	'	'	0	0
Additions to properties	'	'	0	0
Purchase of properties	'	'	0	'
Change in restricted cash related to construction projects	'	'	0	0
Contributions to unconsolidated real estate entity	'	'	0	0
Gain (Loss) on Investments	'	'	'	0
Investments in subsidiaries	'	'	-205,546	-88,247
Additions to investments	'	'	0	100
Proceeds from investments	'	'	0	641
Proceeds from Collection of Notes Receivable	'	'	0	'
Net cash (used in) provided by investing activities	'	'	-205,546	-87,506
Financing Activities	'	'	'	'
Borrowings from secured notes payable	'	'	0	0
Repayments of borrowings from secured notes payable	'	'	0	0
Proceeds from Issuance of Unsecured Debt	'	'	'	0
Principal borrowings from unsecured senior line of credit	'	'	0	0
Repayments of borrowings from unsecured senior line of credit	'	'	0	0
Repayments of Unsecured Debt	'	'	'	0
Transfers to/from parent company	'	'	205,546	85,589
Change in restricted cash related to financings	'	'	0	0
Deferred financing costs paid	'	'	0	0
Proceeds from Issuance of Common Stock	'	'	'	0
Dividends paid on common stock	'	'	0	0
Dividends paid on preferred stock	'	'	0	0
Proceeds from Noncontrolling Interests	'	'	0	'
Payments of Distributions to Affiliates	'	'	0	0
Distributions to noncontrolling interests	'	'	0	0
Net cash provided by (used in) financing activities	'	'	205,546	85,589
Effect of foreign exchange rate changes on cash and cash equivalents	'	'	0	0
Net increase in cash and cash equivalents	'	'	0	-1,913
Cash and cash equivalents at beginning of period	'	'	0	1,913
Cash and cash equivalents at end of period	0	0	0	0
Supplemental Disclosure of Cash Flow Information	'	'	'	'
Cash paid during the period for interest, net of interest capitalized	'	'	0	0
Non-Cash Investing Activities	'	'	'	'
Note receivable from sale of real estate	'	'	'	0
Change in accrued capital expenditures	'	'	0	0
Assumption of secured notes payable in connection with purchase of properties	'	'	0	'
Combined Non- Guarantor Subsidiaries	'	'	'	'
Operating Activities	'	'	'	'
Net income	61,278	55,906	126,126	107,721
Depreciation, Depletion and Amortization	'	'	104,808	90,654
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Gains (Losses) on Extinguishment of Debt	'	0	'	0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	-797	-772	-797	-772
Loss on sale of real estate	'	'	'	121
Amortization of loan fees and costs	'	'	1,762	1,432
Amortization of debt premiums/discounts	'	'	56	206
Amortization of above and below Market Leases	'	'	-1,434	-1,660
Deferred rent	'	'	-24,619	-14,437
Stock compensation expense	'	'	0	0
Equity in income related to subsidiaries	'	'	-2,229	-1,899
Investment gains	'	'	-6,225	-2,514
Investment losses	'	'	3,705	232
Changes in operating assets and liabilities:	'	'	'	'
Restricted cash	'	'	9	382
Tenant receivables	'	'	-735	846
Deferred leasing costs	'	'	-17,452	-22,317
Other assets	'	'	-1,652	-25,512
Intercompany receivables and payables	'	'	'	40
Accounts payable, accrued expenses, and tenant security deposits	'	'	-20,765	29,274
Net cash (used in) provided by operating activities	'	'	160,558	161,797
Investing Activities	'	'	'	'
Proceeds from sale of properties	'	'	17,868	91,019
Additions to properties	'	'	-210,792	-298,927
Purchase of properties	'	'	-97,785	'
Change in restricted cash related to construction projects	'	'	5,650	-8,889
Contributions to unconsolidated real estate entity	'	'	-1,405	-4,889
Gain (Loss) on Investments	'	'	'	-293
Investments in subsidiaries	'	'	-8,095	-1,243
Additions to investments	'	'	-25,358	-14,933
Proceeds from investments	'	'	8,794	8,903
Proceeds from Collection of Notes Receivable	'	'	29,851	'
Net cash (used in) provided by investing activities	'	'	-281,272	-229,252
Financing Activities	'	'	'	'
Borrowings from secured notes payable	'	'	77,762	26,114
Repayments of borrowings from secured notes payable	'	'	-219,427	-31,436
Proceeds from Issuance of Unsecured Debt	'	'	'	0
Principal borrowings from unsecured senior line of credit	'	'	0	0
Repayments of borrowings from unsecured senior line of credit	'	'	0	0
Repayments of Unsecured Debt	'	'	'	0
Transfers to/from parent company	'	'	243,923	65,115
Change in restricted cash related to financings	'	'	1,212	16,634
Deferred financing costs paid	'	'	-266	-362
Proceeds from Issuance of Common Stock	'	'	'	0
Dividends paid on common stock	'	'	0	0
Dividends paid on preferred stock	'	'	0	0
Proceeds from Noncontrolling Interests	'	'	19,410	'
Payments of Distributions to Affiliates	'	'	-595	-596
Distributions to noncontrolling interests	'	'	-1,388	-639
Net cash provided by (used in) financing activities	'	'	120,631	74,830
Effect of foreign exchange rate changes on cash and cash equivalents	'	'	837	-1,960
Net increase in cash and cash equivalents	'	'	754	5,415
Cash and cash equivalents at beginning of period	'	'	42,906	40,491
Cash and cash equivalents at end of period	43,660	45,906	43,660	45,906
Supplemental Disclosure of Cash Flow Information	'	'	'	'
Cash paid during the period for interest, net of interest capitalized	'	'	9,704	11,290
Non-Cash Investing Activities	'	'	'	'
Note receivable from sale of real estate	'	'	'	9,000
Change in accrued capital expenditures	'	'	592	-48,198
Assumption of secured notes payable in connection with purchase of properties	'	'	-48,329	'
Eliminations	'	'	'	'
Operating Activities	'	'	'	'
Net income	-114,738	-103,795	-236,697	-201,801
Depreciation, Depletion and Amortization	'	'	0	0
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Gains (Losses) on Extinguishment of Debt	'	0	'	0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	0	0	0	0
Loss on sale of real estate	'	'	'	0
Amortization of loan fees and costs	'	'	0	0
Amortization of debt premiums/discounts	'	'	0	0
Amortization of above and below Market Leases	'	'	0	0
Deferred rent	'	'	0	0
Stock compensation expense	'	'	0	0
Equity in income related to subsidiaries	'	'	236,697	201,801
Investment gains	'	'	0	0
Investment losses	'	'	0	0
Changes in operating assets and liabilities:	'	'	'	'
Restricted cash	'	'	0	0
Tenant receivables	'	'	0	0
Deferred leasing costs	'	'	0	0
Other assets	'	'	0	188
Intercompany receivables and payables	'	'	'	0
Accounts payable, accrued expenses, and tenant security deposits	'	'	0	-188
Net cash (used in) provided by operating activities	'	'	0	0
Investing Activities	'	'	'	'
Proceeds from sale of properties	'	'	0	0
Additions to properties	'	'	0	0
Purchase of properties	'	'	0	'
Change in restricted cash related to construction projects	'	'	0	0
Contributions to unconsolidated real estate entity	'	'	0	0
Gain (Loss) on Investments	'	'	'	0
Investments in subsidiaries	'	'	449,572	150,704
Additions to investments	'	'	0	0
Proceeds from investments	'	'	0	0
Proceeds from Collection of Notes Receivable	'	'	0	'
Net cash (used in) provided by investing activities	'	'	449,572	150,704
Financing Activities	'	'	'	'
Borrowings from secured notes payable	'	'	0	0
Repayments of borrowings from secured notes payable	'	'	0	0
Proceeds from Issuance of Unsecured Debt	'	'	'	0
Principal borrowings from unsecured senior line of credit	'	'	0	0
Repayments of borrowings from unsecured senior line of credit	'	'	0	0
Repayments of Unsecured Debt	'	'	'	0
Transfers to/from parent company	'	'	-449,572	-150,704
Change in restricted cash related to financings	'	'	0	0
Deferred financing costs paid	'	'	0	0
Proceeds from Issuance of Common Stock	'	'	'	0
Dividends paid on common stock	'	'	0	0
Dividends paid on preferred stock	'	'	0	0
Proceeds from Noncontrolling Interests	'	'	0	'
Payments of Distributions to Affiliates	'	'	0	0
Distributions to noncontrolling interests	'	'	0	0
Net cash provided by (used in) financing activities	'	'	-449,572	-150,704
Effect of foreign exchange rate changes on cash and cash equivalents	'	'	0	0
Net increase in cash and cash equivalents	'	'	0	0
Cash and cash equivalents at beginning of period	'	'	0	0
Cash and cash equivalents at end of period	0	0	0	0
Supplemental Disclosure of Cash Flow Information	'	'	'	'
Cash paid during the period for interest, net of interest capitalized	'	'	0	0
Non-Cash Investing Activities	'	'	'	'
Note receivable from sale of real estate	'	'	'	0
Change in accrued capital expenditures	'	'	0	0
Assumption of secured notes payable in connection with purchase of properties	'	'	$0	'