BioMed Realty L P 10-Q 2 May 14 2014 Q1 Quarterly report Financial data

Document_Entity_Information

Document Entity Information	3 Months Ended
	Mar. 31, 2014	1-May-14
Entity Information [Line Items]	'	'
Entity Registrant Name	'BioMed Realty Trust Inc	'
Entity Central Index Key	'0001289236	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	192,506,626
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
BIOMED REALTY, L.P.	'	'
Entity Information [Line Items]	'	'
Entity Registrant Name	'BioMed Realty L P	'
Entity Central Index Key	'0001301932	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments in real estate, net	$5,235,036	$5,217,902
Investments in unconsolidated partnerships	31,461	32,137
Parent Company	'	'
Investments in real estate, net	5,235,036	5,217,902
Investments in unconsolidated partnerships	31,461	32,137
Cash and cash equivalents	59,121	34,706
Accounts receivable, net	10,719	8,421
Accrued straight-line rents, net	178,114	173,779
Deferred leasing costs, net	189,527	198,067
Other assets	371,453	307,589
Total assets	6,075,431	5,972,601
Liabilities [Abstract]	'	'
Mortgage notes payable, net	706,013	709,324
Exchangeable senior notes	180,000	180,000
Unsecured senior notes, net	895,312	895,083
Unsecured senior term loans	760,066	758,786
Unsecured line of credit	226,000	128,000
Accounts payable, accrued expenses and other liabilities	333,157	314,383
Total liabilities	3,100,548	2,985,576
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]	'	'
Common stock, $.01 par value, 250,000,000 shares authorized, 192,502,965 shares and 192,115,002 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	1,925	1,921
Additional paid-in capital	3,554,504	3,554,558
Accumulated other comprehensive loss, net	-19,973	-32,923
Dividends in excess of earnings	-612,864	-583,569
Total stockholders' equity	2,923,592	2,939,987
Noncontrolling interests / Noncontrolling interests deficit	51,291	47,038
Total equity / capital	2,974,883	2,987,025
Total liabilities and equity / capital	6,075,431	5,972,601
BIOMED REALTY, L.P.	'	'
Investments in real estate, net	5,235,036	5,217,902
Investments in unconsolidated partnerships	31,461	32,137
Cash and cash equivalents	59,121	34,706
Accounts receivable, net	10,719	8,421
Accrued straight-line rents, net	178,114	173,779
Deferred leasing costs, net	189,527	198,067
Other assets	371,453	307,589
Total assets	6,075,431	5,972,601
Liabilities [Abstract]	'	'
Mortgage notes payable, net	706,013	709,324
Exchangeable senior notes	180,000	180,000
Unsecured senior notes, net	895,312	895,083
Unsecured senior term loans	760,066	758,786
Unsecured line of credit	226,000	128,000
Accounts payable, accrued expenses and other liabilities	333,157	314,383
Total liabilities	3,100,548	2,985,576
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]	'	'
Limited partners' capital, 5,405,474 and 5,415,974 units issued and outstanding at March 31, 2014 and December 31, 2013, respectively	45,204	45,708
General partner's capital, 192,502,965 and 192,115,002 units issued and outstanding at March 31, 2014 and December 31, 2013, respectively	2,940,948	2,970,650
Accumulated other comprehensive loss, net	-17,356	-30,663
Total partners' capital	2,968,796	2,985,695
Noncontrolling interests / Noncontrolling interests deficit	6,087	1,330
Total equity / capital	2,974,883	2,987,025
Total liabilities and equity / capital	$6,075,431	$5,972,601

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parentheticals) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Parent Company	'	'
Common Stock, Par or Stated Value Per Share	$0.01	$0.01
Common Stock, Shares Authorized	250,000,000	250,000,000
Common Stock, Shares, Issued	192,502,965	192,115,002
BIOMED REALTY, L.P.	'	'
Limited Partners' Capital Account, Units Issued	5,405,474	5,415,974
Limited Partners' Capital Account, Units Outstanding	5,405,474	5,415,974
General Partners' Capital Account, Units Issued	192,502,965	192,115,002
General Partners' Capital Account, Units Outstanding	192,502,965	192,115,002
Common Stock | Parent Company	'	'
Common Stock, Shares Outstanding	192,502,965	192,115,002

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Expenses:	'	'
Equity in net loss of unconsolidated partnerships	($138)	($319)
Parent Company	'	'
Revenues:	'	'
Rental	120,026	102,956
Tenant recoveries	38,735	32,637
Other revenue	10,115	24,857
Total revenues	168,876	160,450
Expenses:	'	'
Rental operations	52,523	40,553
Depreciation and amortization	62,409	60,764
General and administrative	11,942	10,028
Acquisition-related expenses	1,250	2,236
Total expenses	128,124	113,581
Income from operations	40,752	46,869
Equity in net loss of unconsolidated partnerships	-138	-319
Interest expense, net	-28,010	-25,902
Other expense	8,163	-3,190
Net income / (loss)	20,767	17,458
Net (income) / loss attributable to noncontrolling interests	-1,934	-146
Net income / (loss) attributable to the Company/Operating Partnership	18,833	17,312
Preferred stock dividends / unit distributions	'	-2,393
Cost on redemption of preferred stock / units	'	-6,531
Net income / (loss) available to common stockholders/unitholders	18,833	8,388
Net income / (loss) per share / unit available to common stockholders / unitholders	$0.10	$0.05
Weighted Average Number of Shares Outstanding, Basic	190,905,867	159,692,470
Weighted Average Number of Shares Outstanding, Diluted	196,545,536	162,713,677
BIOMED REALTY, L.P.	'	'
Revenues:	'	'
Rental	120,026	102,956
Tenant recoveries	38,735	32,637
Other revenue	10,115	24,857
Total revenues	168,876	160,450
Expenses:	'	'
Rental operations	52,523	40,553
Depreciation and amortization	62,409	60,764
General and administrative	11,942	10,028
Acquisition-related expenses	1,250	2,236
Total expenses	128,124	113,581
Income from operations	40,752	46,869
Equity in net loss of unconsolidated partnerships	-138	-319
Interest expense, net	-28,010	-25,902
Other expense	8,163	-3,190
Net income / (loss)	20,767	17,458
Net (income) / loss attributable to noncontrolling interests	-1,413	8
Net income / (loss) attributable to the Company/Operating Partnership	19,354	17,466
Preferred stock dividends / unit distributions	'	-2,393
Cost on redemption of preferred stock / units	'	-6,531
Net income / (loss) available to common stockholders/unitholders	$19,354	$8,542
Net income / (loss) per share / unit available to common stockholders / unitholders	$0.10	$0.05
Weighted Average Number of Shares Outstanding, Basic	196,316,241	162,612,998
Weighted Average Number of Shares Outstanding, Diluted	196,545,536	162,710,786

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	$162,000	'
Other Comprehensive Income (Loss), Net of Tax	10,100,000	'
Parent Company	'	'
Net income / (loss)	20,767,000	17,458,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	238,000	-2,182,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	-590,000	-137,000
Amortization of Other Deferred Charges	1,691,000	1,718,000
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	-9,322,000	'
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	24,634,000	-168,000
Other Comprehensive Income (Loss), Net of Tax	16,651,000	-769,000
Comprehensive Income / loss, Net of Tax, Including Portion Attributable to Noncontrolling Interest	37,418,000	16,689,000
Comprehensive (income) / loss, Net of Tax, Attributable to Noncontrolling Interest	-5,635,000	-132,000
Comprehensive income / (loss), Net of Tax, Attributable to Parent	31,783,000	16,557,000
BIOMED REALTY, L.P.	'	'
Net income / (loss)	20,767,000	17,458,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	238,000	-2,182,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	-590,000	-137,000
Amortization of Other Deferred Charges	1,691,000	1,718,000
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	-9,322,000	'
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	24,634,000	-168,000
Other Comprehensive Income (Loss), Net of Tax	16,651,000	-769,000
Comprehensive Income / loss, Net of Tax, Including Portion Attributable to Noncontrolling Interest	37,418,000	16,689,000
Comprehensive (income) / loss, Net of Tax, Attributable to Noncontrolling Interest	-4,757,000	8,000
Comprehensive income / (loss), Net of Tax, Attributable to Parent	32,661,000	16,697,000
Interest Rate Swaps | BIOMED REALTY, L.P.	'	'
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	($590,000)	'

Consolidated_Statement_of_Equi

Consolidated Statement of Equity (USD $)

Total

Parent Company

BIOMED REALTY, L.P.

Common Stock

Additional Paid-In Capital

Accumulated Other Comprehensive (Loss)/Income

Accumulated Other Comprehensive (Loss)/Income

Dividends in Excess of Earnings

Total Stockholders'/Partner's Equity

Total Stockholders'/Partner's Equity

Noncontrolling Interest

Noncontrolling Interest

Limited Partner

General Partner [Member]

Forward Starting Swaps

Interest Rate Swaps

Parent Company

Parent Company

Parent Company

BIOMED REALTY, L.P.

Parent Company

Parent Company

BIOMED REALTY, L.P.

Parent Company

BIOMED REALTY, L.P.

Common Stock

Common Stock

BIOMED REALTY, L.P.

BIOMED REALTY, L.P.

BIOMED REALTY, L.P.

BIOMED REALTY, L.P.

Balance - value - period start at Dec. 31, 2013

'

$2,987,025,000

$2,987,025,000

$1,921,000

$3,554,558,000

($32,923,000)

($30,663,000)

($583,569,000)

$2,939,987,000

$2,985,695,000

$47,038,000

$1,330,000

$45,708,000

$2,970,650,000

'

'

Balance - units - period start at Dec. 31, 2013

'

'

'

'

'

'

'

'

'

'

'

'

5,415,974

192,115,002

'

'

Balance - shares - period start at Dec. 31, 2013

'

'

'

192,115,002

'

'

'

'

'

'

'

'

'

'

'

'

Stock Issued During Period, Value, New Issues

'

-49,000

-49,000

'

-49,000

'

'

'

-49,000

-49,000

'

'

'

-49,000

'

'

Net issuances of unvested restricted common stock/OP units - shares

'

'

'

377,463

'

'

'

'

'

'

'

'

'

377,463

'

'

Net issuances of unvested restricted common stock/OP units - value

'

-3,782,000

-3,782,000

4,000

-3,786,000

'

'

'

-3,782,000

-3,782,000

'

'

'

-3,782,000

'

'

Conversion of OP units to common stock - shares

'

'

'

-10,500

'

'

'

'

'

'

'

'

-10,500

-10,500

'

'

Conversion of OP units to common stock - value

'

'

'

'

-51,000

'

'

'

-51,000

'

51,000

'

51,000

-51,000

'

'

Vesting of share-based awards

'

3,750,000

3,750,000

'

3,750,000

'

'

'

3,750,000

3,750,000

'

'

'

3,750,000

'

'

Reallocation of equity to noncontrolling interests/limited partners

'

'

'

'

82,000

'

'

'

82,000

'

-82,000

'

275,000

-275,000

'

'

Common stock dividends

'

-48,128,000

'

'

'

'

'

-48,128,000

-48,128,000

'

'

'

'

'

'

'

OP unit distributions

'

-1,351,000

-49,479,000

'

'

'

'

'

'

-49,479,000

-1,351,000

'

-1,351,000

-48,128,000

'

'

Net income / (loss)

'

20,767,000

20,767,000

'

'

'

'

18,833,000

18,833,000

19,354,000

1,934,000

1,413,000

521,000

18,833,000

'

'

Other Comprehensive Income (Loss), Foreign currency translation adjustment

'

238,000

238,000

'

'

232,000

238,000

'

232,000

238,000

6,000

'

'

'

'

'

Marketable Securities, Realized Gain (Loss)

'

-9,322,000

-9,322,000

'

'

-7,784,000

-7,784,000

'

-7,784,000

-7,784,000

-1,538,000

-1,538,000

'

'

'

'

Unrealized loss on equity securities

'

24,634,000

24,634,000

'

'

19,430,000

19,752,000

'

19,430,000

19,752,000

5,204,000

4,882,000

'

'

'

'

Amortization of deferred interest costs

'

1,691,000

'

'

'

1,646,000

1,691,000

'

1,646,000

1,691,000

45,000

'

'

'

1,691,000

'

Unrealized gain on derivative instruments, net

162,000

-590,000

-590,000

'

'

-574,000

-590,000

'

-574,000

-590,000

-16,000

'

'

'

'

-590,000

Balance - value - period end at Mar. 31, 2014

'

$2,974,883,000

$2,974,883,000

$1,925,000

$3,554,504,000

($19,973,000)

($17,356,000)

($612,864,000)

$2,923,592,000

$2,968,796,000

$51,291,000

$6,087,000

$45,204,000

$2,940,948,000

'

'

Balance - units - period end at Mar. 31, 2014

'

'

'

'

'

'

'

'

'

'

'

'

5,405,474

192,502,965

'

'

Balance - shares - period end at Mar. 31, 2014

'

'

'

192,502,965

'

'

'

'

'

'

'

'

'

'

'

'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
BIOMED REALTY, L.P.	'	'	'	'
Interest Paid, Capitalized	'	'	$4,192	$2,840
Operating Activities	'	'	'	'
Net income / (loss)	20,767	17,458	'	'
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'	'
Depreciation and amortization	62,409	60,764	'	'
Allowance for doubtful accounts	526	501	'	'
Non-cash revenue adjustments	481	5,803	'	'
Other non-cash adjustments	-4,886	6,457	'	'
Compensation expense related to restricted common stock and LTIP units / share-based payments	3,750	3,011	'	'
Distributions representing a return on capital from unconsolidated partnerships	203	59	'	'
Change in operating assets and liabilities	'	'	'	'
Accounts receivable	-2,482	-31,822	'	'
Accrued straight-line rents	-4,676	-3,555	'	'
Deferred leasing costs	-1,754	-1,520	'	'
Other assets	1,206	314	'	'
Accounts payable, accrued expenses and other liabilities	2,194	2,823	'	'
Net cash provided by operating activities	77,738	60,293	'	'
Investing activities	'	'	'	'
Purchases of investments in real estate and related intangible assets	'	-123,841	'	'
Capital expenditures	-69,843	-39,250	'	'
Contributions from historic tax credit transactions, net of deferred costs	15,502	'	'	'
Draws on construction loan receivable	-39,584	-34,310	'	'
Contributions to unconsolidated partnerships, net	-4	-336	'	'
Purchases of debt and equity securities	-2,971	-5,395	'	'
Proceeds from the sale of debt and equity securities	13,952	'	'	'
Payments for (Proceeds from) Deposits on Real Estate Acquisitions	-16,100	0	'	'
Net cash used in investing activities	-99,048	-203,132	'	'
Financing activities	'	'	'	'
Proceeds from issuance of OP units	'	286,992	'	'
Redemption of Series A preferred stock	'	-198,000	'	'
Unsecured line of credit proceeds	130,000	284,000	'	'
Unsecured line of credit payments	-32,000	-187,000	'	'
Principal payments on mortgage notes payable	-2,776	-2,073	'	'
Dividends paid to common stockholders / unitholders	-49,383	-36,957	'	'
Dividends paid to preferred stockholders / unitholders	'	-6,044	'	'
Net cash provided by financing activities	45,841	140,918	'	'
Effect of exchange rate changes on cash and cash equivalents	-116	497	'	'
Net increase / (decrease) in cash and cash equivalents	24,415	-1,424	'	'
Cash and cash equivalents at beginning of period	34,706	19,976	19,976	'
Cash and cash equivalents at end of period	59,121	18,552	34,706	19,976
Supplemental disclosure of cash flow information:	'	'	'	'
Cash paid during the period for interest (net of amounts capitalized of $4,192 and $2,840 during the three months ended March 31, 2014 and 2013, respectively)	21,593	16,654	'	'
Supplemental disclosure of non-cash investing and financing activities:	'	'	'	'
Accrual for common stock dividends / unit distributions declared	49,479	40,413	'	'
Accrued additions to real estate and related intangible assets	60,171	31,928	'	'
Parent Company	'	'	'	'
Interest Paid, Capitalized	'	'	4,192	2,840
Operating Activities	'	'	'	'
Net income / (loss)	20,767	17,458	'	'
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'	'
Depreciation and amortization	62,409	60,764	'	'
Allowance for doubtful accounts	526	501	'	'
Non-cash revenue adjustments	481	5,803	'	'
Other non-cash adjustments	-4,886	6,457	'	'
Compensation expense related to restricted common stock and LTIP units / share-based payments	3,750	3,011	'	'
Distributions representing a return on capital from unconsolidated partnerships	203	59	'	'
Change in operating assets and liabilities	'	'	'	'
Accounts receivable	-2,482	-31,822	'	'
Accrued straight-line rents	-4,676	-3,555	'	'
Deferred leasing costs	-1,754	-1,520	'	'
Other assets	1,206	314	'	'
Accounts payable, accrued expenses and other liabilities	2,194	2,823	'	'
Net cash provided by operating activities	77,738	60,293	'	'
Investing activities	'	'	'	'
Purchases of investments in real estate and related intangible assets	'	-123,841	'	'
Capital expenditures	-69,843	-39,250	'	'
Contributions from historic tax credit transactions, net of deferred costs	15,502	'	'	'
Draws on construction loan receivable	-39,584	-34,310	'	'
Contributions to unconsolidated partnerships, net	-4	-336	'	'
Purchases of debt and equity securities	-2,971	-5,395	'	'
Proceeds from the sale of debt and equity securities	13,952	'	'	'
Payments for (Proceeds from) Deposits on Real Estate Acquisitions	-16,100	0	'	'
Net cash used in investing activities	-99,048	-203,132	'	'
Financing activities	'	'	'	'
Proceeds from common stock offering	'	299,402	'	'
Payment of offering costs	'	-12,410	'	'
Redemption of Series A preferred stock	'	-198,000	'	'
Unsecured line of credit proceeds	130,000	284,000	'	'
Unsecured line of credit payments	-32,000	-187,000	'	'
Principal payments on mortgage notes payable	-2,776	-2,073	'	'
Distributions to operating partnership unit and LTIP unit holders	-1,354	-689	'	'
Dividends paid to common stockholders / unitholders	-48,029	-36,268	'	'
Dividends paid to preferred stockholders / unitholders	'	-6,044	'	'
Net cash provided by financing activities	45,841	140,918	'	'
Effect of exchange rate changes on cash and cash equivalents	-116	497	'	'
Net increase / (decrease) in cash and cash equivalents	24,415	-1,424	'	'
Cash and cash equivalents at beginning of period	34,706	19,976	19,976	'
Cash and cash equivalents at end of period	59,121	18,552	34,706	19,976
Supplemental disclosure of cash flow information:	'	'	'	'
Cash paid during the period for interest (net of amounts capitalized of $4,192 and $2,840 during the three months ended March 31, 2014 and 2013, respectively)	21,593	16,654	'	'
Supplemental disclosure of non-cash investing and financing activities:	'	'	'	'
Accrual for common stock dividends / unit distributions declared	48,128	39,727	'	'
Accrual for distributions declared for operating partnership unit and LTIP unit holders	1,351	686	'	'
Accrued additions to real estate and related intangible assets	$60,171	$31,928	'	'

Organization_of_the_Parent_Com

Organization of the Parent Company and Description of Business	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	Organization of the Parent Company and Description of Business
	BioMed Realty Trust, Inc., a Maryland corporation (the “Parent Company”), operates as a fully integrated, self-administered and self-managed real estate investment trust (“REIT”) focused on acquiring, developing, owning, leasing and managing laboratory and office space for the life science industry principally through its subsidiary, BioMed Realty, L.P., a Maryland limited partnership (the “Operating Partnership” and together with the Parent Company referred to as the “Company”). The Company’s tenants primarily include biotechnology and pharmaceutical companies, scientific research institutions, government agencies and other entities involved in the life science industry. The Company’s properties are generally located in markets with well-established reputations as centers for scientific research, including Boston, San Francisco, San Diego, Maryland, New York/New Jersey, Pennsylvania, North Carolina, Seattle and Cambridge (United Kingdom) and, through Wexford Science & Technology, LLC and related entities (collectively, "Wexford"), with universities and their related medical systems.
	The Parent Company is the sole general partner of the Operating Partnership and, as of March 31, 2014, owned a 97.3% interest in the Operating Partnership. The remaining 2.7% interest in the Operating Partnership is held by limited partners. Each partner’s percentage interest in the Operating Partnership is determined based on the number of operating partnership units and long-term incentive plan units (“LTIP units” and together with the operating partnership units, the “OP units”) owned as compared to total OP units (and potentially issuable OP units, as applicable) outstanding as of each period end and is used as the basis for the allocation of net income or loss to each partner.
	On April 4, 2014, the Company completed an investment in two properties, 300 George Street and 100 College Street, in New Haven, Connecticut. The 300 George Street property is a 519,000 square foot laboratory and office building. The 100 College Street property, currently under construction, is expected to be a 508,000 square foot laboratory and office building. The total project investment is expected to be approximately $308 million, comprised of (1) approximately $206 million in cash, assumptions of mortgage notes payable and a construction loan in connection with the Company's investment, and a continuing minority partnership interest of Winstanley Enterprises LLC, which will also continue to provide construction and property management services for the properties, and (2) approximately $102 million of remaining construction costs. As of April 4, 2014, Winstanley Enterprises LLC retained approximately 7% and 25% continuing minority partnership interests in the 300 George Street and 100 College Street properties, respectively. Upon completion of construction of the 100 College Street property and repayment of the related construction loan, the Company expects Winstanley Enterprises LLC’s minority partnership interest in the 100 College Street property to be reduced to approximately 2.5%.

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis of Presentation and Summary of Significant Accounting Policies	'
	Basis of Presentation and Summary of Significant Accounting Policies
	The accompanying interim financial statements are unaudited, but have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and in conjunction with the rules and regulations of the U.S. Securities and Exchange Commission. Accordingly, they do not include all the disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments and eliminations, consisting of normal recurring adjustments necessary for a fair presentation of the financial statements for these interim periods have been recorded. These financial statements should be read in conjunction with the audited consolidated financial statements and notes therein included in the Company’s annual report on Form 10-K for the year ended December 31, 2013.
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, partnerships and limited liability companies it controls, and variable interest entities (“VIEs”) for which the Company has determined itself to be the primary beneficiary. All material intercompany transactions and balances have been eliminated. The Company consolidates entities the Company controls and records a noncontrolling interest for the portions not owned by the Company. Control is determined, where applicable, by the sufficiency of equity invested and the rights of the equity holders, and by the ownership of a majority of the voting interests, with consideration given to the existence of approval or veto rights granted to the minority stockholder. If the minority stockholder holds substantive participating rights, it overcomes the presumption of control by the majority voting interest holder. In contrast, if the minority stockholder simply holds protective rights (such as consent rights over certain actions), it does not overcome the presumption of control by the majority voting interest holder.
	Assets and liabilities of subsidiaries outside the United States with non-U.S. dollar functional currencies are translated into U.S. dollars using exchange rates as of the balance sheet dates. Income and expenses are translated using the average exchange rates for the reporting period. Foreign currency translation adjustments are recorded as a component of other comprehensive income. For the three months ended March 31, 2014 and 2013, total revenues from properties outside the United States were $4.8 million and $4.5 million, respectively, which represented 2.8% of the Company's total revenues during each period. The Company’s net investments in properties outside the United States were $190.7 million and $190.2 million at March 31, 2014 and December 31, 2013, respectively.
	Investments in Partnerships and Limited Liability Companies
	The Company has determined that it is the primary beneficiary in five VIEs (excluding certain VIEs through its ownership of Wexford), consisting of single-tenant properties in which the tenant has a fixed-price purchase option, which are consolidated and reflected in the accompanying consolidated financial statements. Selected financial data of these VIEs at March 31, 2014 and December 31, 2013 consist of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	339,284		$	336,832
	Total assets	378,961			375,443
	Total debt	142,564			143,067
	Total liabilities	156,186			154,953
	Wexford - Variable Interest Entities
	Wexford is a party to certain contractual arrangements with tax credit investors (“TCIs”) that were established to enable the TCIs to receive the benefits of historic tax credits (“HTCs”) and/or new market tax credits (“NMTCs”) for certain properties owned by Wexford. At March 31, 2014, Wexford owned nine properties that had syndicated HTCs or NMTCs, or both, to TCIs.
	Historic Tax Credits and New Market Tax Credits
	Capital contributions are made by TCIs into special purpose entities that ultimately invest these funds in the entity that owns the subject property that generates the tax credits. The TCIs are allocated substantially all of the tax credits and hold only a noncontrolling interest in the economic risk and rewards of the special purpose entities. HTCs are delivered to the TCI upon substantial completion of the project. NMTCs are allowed for up to 39% of a qualified investment and are delivered to the TCI after the investment has been funded and spent on a qualified business. HTCs are subject to 20% recapture per year beginning one year after the completion of the historic rehabilitation of the subject property. NMTCs are subject to 100% recapture until the end of the seventh year following the qualifying investment. The Company has provided the TCIs with certain guarantees which protect the TCIs from loss should a tax credit recapture event occur. The contractual arrangements with the TCIs include a put/call provision whereby the Company may be obligated or entitled to repurchase the ownership interest of the TCIs in the special purpose entities at the end of the tax credit recapture period. The Company anticipates that either the TCIs will exercise their put rights or the Company will exercise its call rights; however, the Company believes that the put rights are more likely to be exercised.
	The Company has determined that the special purpose entities are VIEs, since there is insufficient capital to finance their activities without further subordinated financial support. The Company has determined that it is the primary beneficiary of these VIEs, because it has the authority to direct the activities which most significantly impact their economic performance.
	The portion of the TCI’s capital contribution that is attributed to the put is recorded at fair-value at inception and is accreted to the expected put price as interest expense in the consolidated statement of income. At March 31, 2014, approximately $4.5 million of put liabilities were included in other liabilities in the consolidated balance sheets. The remaining balance of the TCI’s capital contribution is initially recorded in other liabilities in the consolidated balance sheets and is reclassified, upon delivery of the tax credit to the TCI, to reduce the carrying value of the subject property, net of allocated expenses. Direct and incremental costs incurred in structuring the transaction, consisting of third-party legal, accounting and other professional fees are deferred and will be recognized as an increase in the cost basis of the subject property upon the recognition of the related tax credit as discussed above. During the quarter ended March 31, 2014, $15.5 million of tax credits, net of costs and estimated put payments, were contributed by TCIs and recorded as other liabilities in the consolidated balance sheets, of which $12.8 million in tax credits were delivered to the TCIs and reclassified as a reduction of the carrying value of the subject property.
	The Company has determined that certain special purpose entities owning properties under development are VIEs, since there is insufficient capital to finance the remaining development activities without further subordinated financial support. The Company has determined it is the primary beneficiary of these VIEs, because it has the authority to direct the activities which most significantly impact their economic performance. Selected financial data of the VIEs at March 31, 2014 consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	181,458		$	177,901
	Total assets	193,789			198,968
	Total liabilities	63,877			60,197
	Investments in Real Estate, Net
	Investments in real estate, net consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Land	$	717,328		$	713,955
	Land under development	116,220			119,325
	Buildings and improvements	4,907,630			4,854,175
	Construction in progress	329,803			316,025
		6,070,981			6,003,480
	Accumulated depreciation	(835,945		)	(785,578		)
		$	5,235,036		$	5,217,902
	Impairment of Long-Lived Assets and Long-Lived Assets to be Disposed
	The Company reviews long-lived assets and certain identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The review of recoverability is based on an estimate of the future undiscounted cash flows (excluding interest charges) expected to result from the long-lived asset’s use and eventual disposition. These cash flows consider factors such as expected future operating income, trends and prospects, as well as the effects of leasing demand, competition and other factors. If impairment exists due to the inability to recover the carrying value of a long-lived asset, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair-value of the property. The Company is required to make subjective assessments as to whether there are impairments in the values of its investments in long-lived assets. These assessments have a direct impact on the Company’s net income because recording an impairment loss results in an immediate negative adjustment to net income. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Although the Company’s strategy is to hold its properties over the long-term, if the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized to reduce the property to the lower of the carrying amount or fair-value, and such loss could be material. As of and for the three months ended March 31, 2014, no assets have been identified as impaired and no such impairment losses have been recognized.
	Deferred Leasing Costs, Net
	Leasing commissions and other direct costs associated with obtaining new or renewal leases are recorded at cost and amortized on a straight-line basis over the terms of the respective leases, with remaining terms ranging from less than one year to approximately 20 years as of March 31, 2014. Deferred leasing costs also include the net carrying value of acquired in-place leases and acquired management agreements.
	Deferred leasing costs, net at March 31, 2014 consisted of the following (in thousands):
		Balance at			Accumulated
		March 31, 2014			Amortization			Net
	Acquired in-place leases	$	365,944		$	(243,437	)	$	122,507
	Acquired management agreements	25,801			(20,502		)	5,299
	Deferred leasing and other direct costs	94,273			(32,552		)	61,721
		$	486,018		$	(296,491	)	$	189,527
	Deferred leasing costs, net at December 31, 2013 consisted of the following (in thousands):
		Balance at			Accumulated
		December 31, 2013			Amortization			Net
	Acquired in-place leases	$	365,753		$	(233,935	)	$	131,818
	Acquired management agreements	25,801			(20,053		)	5,748
	Deferred leasing and other direct costs	91,142			(30,641		)	60,501
		$	482,696		$	(284,629	)	$	198,067
	Investments
	Investments in equity securities, which are included in other assets on the accompanying consolidated balance sheets, consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Available-for-sale securities, historical cost	$	7,191		$	8,543
	Unrealized gain, net	26,088			11,023
	Available-for-sale securities, fair-value (1)	33,279			19,566
	Privately-held securities, cost basis	17,107			18,485
	Total equity securities	$	50,386		$	38,051
-1	Determination of fair-value is classified as Level 1 in the fair-value hierarchy based on the use of quoted prices in active markets.
The Company holds investments in available-for-sale securities of certain publicly-traded companies. Certain of these investments have fair-values less than the Company’s cost basis, net of previous other-than-temporary impairment in these securities due to decreases in their respective stock prices during the three months ended March 31, 2014. However, management has the intent and ability to retain the investments for a period of time sufficient to allow for an anticipated recovery in their market value. Management will continue to periodically evaluate whether any investment, the fair-value of which is less than the Company’s cost basis, should be considered other-than-temporarily impaired. If other-than-temporary impairment is considered to exist, the related unrealized loss will be reclassified from accumulated other comprehensive loss and recorded as a reduction of net income.
The Company also holds investments in securities of certain privately-held companies and funds, which are recorded at cost basis due to the Company’s lack of control or significant influence over such companies and funds.
During the three months ended March 31, 2014, the Company recorded a $1.3 million impairment charge, which is included in other expense in the consolidated statements of income. The impairment charge related to the Company’s investment in a privately-held company. Other than this investment there were no identified events or changes in circumstances that may have a significant adverse effect on the carrying value of the Company’s cost basis investments and therefore, no evaluation of impairment was performed during the three months ended March 31, 2014 on the Company’s remaining cost basis investments.
Construction Loan Receivable
The Company has a $255.0 million interest in a $355.0 million construction loan secured by first priority mortgages on a 1.1 million square foot laboratory, office and retail development project located in Boston, Massachusetts, which is 95% leased to Vertex Pharmaceuticals Incorporated to serve as its new corporate headquarters (the "Construction Loan").
The Construction Loan matures on September 30, 2014, with two one -year extension options exercisable at the borrower’s election after paying the lenders an extension fee on the then-outstanding principal amount. The Construction Loan bears interest on the outstanding principal amount at a floating rate equal to the greater of (1) reserve adjusted LIBOR plus 550 basis points and (2) 6.5%. In addition, the borrower is required to pay a fee to the lenders based on a specified percentage of the average daily unfunded amount of the Construction Loan. The borrower may prepay the Construction Loan in part under certain circumstances, and may prepay the Construction Loan in full with prior notice and a prepayment fee to the lenders. As of March 31, 2014 and December 31, 2013, the Company had invested approximately $191.3 million and $151.8 million, respectively, in the Construction Loan, which are included in other assets on the Company's consolidated balance sheets.
Lease Termination
During the three months ended March 31, 2014 and 2013, the Company recorded lease termination revenue, net of write-offs of lease intangibles, included in other revenue on the consolidated statement of income of approximately $5.5 million and $24.0 million, respectively. Lease termination revenue for the three months ended March 31, 2014 primarily related to the early termination of leases at the Company's 4570 Executive Drive property. Lease termination revenue for the three months ended March 31, 2013 primarily related to the termination of a lease with Elan Corporation at the Company’s Science Center at Oyster Point property for which Elan paid the Company $46.5 million. The impact of the Elan lease termination was recognized through the date of the termination of the lease in April 2013.
Management’s Estimates
Management has made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reporting of revenue and expenses during the reporting period to prepare these consolidated financial statements in conformity with GAAP. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and reported amounts of revenue and expenses that are not readily apparent from other sources. Actual results could differ from those estimates under different assumptions or conditions.

Equity_of_the_Parent_Company

Equity of the Parent Company	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Equity of the Parent Company	'
	Equity of the Parent Company
	During the three months ended March 31, 2014, the Parent Company issued restricted stock awards to the Company’s employees totaling 557,237 shares of common stock (190,062 shares of common stock were surrendered to the Company and subsequently retired in lieu of cash payments for taxes due on the vesting of restricted stock and 2,693 shares were forfeited during the same period), which are included in the total of common stock outstanding as of the period end.
	The Parent Company awarded units to certain of its executive officers (the “Performance Units”), which represent a contingent right to receive one share of the Parent Company’s common stock if vesting conditions are satisfied. Outstanding Performance Units vest ratably over two or three year periods (each, a “Performance Period”) based upon the Parent Company’s total stockholder return relative to its peer group (the "Market Conditions"). The grant date fair-value of the Performance Units was estimated using a Monte Carlo simulation which considered the likelihood of achieving the Market Conditions. The expected value of the Performance Units on the grant date was determined by simulating the total stockholder return for the Parent Company and the peer group, considering the stock price variance for each of the peer group companies compared to each other and the Parent Company. In January 2014, of the 136,296 Performance Units which were originally granted to certain executive officers in January 2012 and represent the maximum number of Performance Units that could have vested, 20,224 Performance Units vested (resulting in the issuance of 20,224 shares of the Parent Company’s common stock (7,243 shares issued in connection with the vesting of the Performance Units were surrendered to the Company and subsequently retired in lieu of cash payments for taxes due on the vesting of Performance Units) and the remaining 116,072 Performance Units were forfeited, based on the Parent Company’s total stockholder return relative to its peer group for the two years ended December 31, 2013. During the three months ended March 31, 2014, the Parent Company awarded 494,410 Performance Units which represent the maximum number of Performance Units that may vest and which vest over a three-year Performance Period. The grant date fair-value of these awards of approximately $3.8 million will be recognized as compensation expense on a straight-line basis over each respective Performance Period. The total compensation remaining on the Performance Units granted during the three months ended March 31, 2014 to be expensed in future periods over a weighted-average term of approximately 2.8 years was $3.5 million as of March 31, 2014. No dividends will be paid or accrued on the Performance Units, and shares of the Parent Company's common stock will not be issued until vesting of the Performance Units occurs.
	Common Stock, Operating Partnership Units and LTIP Units
	As of March 31, 2014, the Company had outstanding 192,502,965 shares of the Parent Company’s common stock and 5,083,400 and 322,074 operating partnership and LTIP units, respectively (excluding operating partnership units held by the Parent Company). A share of the Parent Company’s common stock and the operating partnership and LTIP units have essentially the same economic characteristics as they share equally in the total net income or loss and distributions of the Operating Partnership.
	Dividends and Distributions
	The following table lists the dividends and distributions declared by the Parent Company and the Operating Partnership during the three months ended March 31, 2014:
	Declaration Date		Securities Class		Amount Per				Period Covered		Dividend and		Dividend and
					Share/Unit						Distribution		Distribution Amount
											Payable Date
													(In thousands)
	March 17, 2014		Common stock and OP units		$	0.25			January 1, 2014 to March 31, 2014		April 15, 2014		$	49,479
	Changes in Accumulated Other Comprehensive Loss by Component
	The following table shows the changes in accumulated other comprehensive loss for the Parent Company for the three months ended March 31, 2014, by component (in thousands):
		Foreign currency translation adjustments				Unrealized gains on available-for-sale securities				Gain / (loss) on derivative instruments				Total
	Balance at December 31, 2013	$	3,905			$	8,938			$	(45,766	)		$	(32,923	)
	Other comprehensive income / (loss) before reclassifications	238				24,634				$	(1,449	)		23,423
	Amounts reclassified from accumulated other comprehensive income (1)	—				(9,322		)		$	2,550			(6,772		)
	Net other comprehensive income	238				15,312				1,101				16,651
	Net other comprehensive income allocable to noncontrolling interests	(6		)		(3,666		)		(29		)		(3,701		)
	Balance as of March 31, 2014	$	4,137			$	20,584			$	(44,694	)		$	(19,973	)
	-1	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.
	Noncontrolling Interests
	Noncontrolling interests on the consolidated balance sheets of the Parent Company relate primarily to the OP units in the Operating Partnership that are not owned by the Parent Company. With respect to the noncontrolling interests in the Operating Partnership, noncontrolling interests with redemption provisions that permit the issuer to settle in either cash or common stock at the option of the issuer are further evaluated to determine whether temporary or permanent equity classification on the balance sheet is appropriate. Because the OP units comprising the noncontrolling interests contain such a provision, the Company evaluated this guidance, including the requirement to settle in unregistered shares, and determined that the OP units meet the requirements to qualify for presentation as permanent equity.
	The Company evaluates individual redeemable noncontrolling interests for the ability to continue to recognize the noncontrolling interest as permanent equity in the consolidated balance sheets. Any redeemable noncontrolling interest that fails to qualify as permanent equity will be reclassified as temporary equity and adjusted to the greater of (1) the carrying amount, or (2) its redemption value at the end of the period in which the determination is made.
	The redemption value of the OP units not owned by the Parent Company, had such units been redeemed at March 31, 2014, was approximately $109.0 million based on the average closing price of the Parent Company’s common stock of $20.16 per share for the ten consecutive trading days immediately preceding March 31, 2014.
	The following table shows the vested ownership interests in the Operating Partnership:
		March 31, 2014						December 31, 2013
		Operating Partnership Units and LTIP Units			Percentage of Total			Operating Partnership Units and LTIP Units			Percentage of Total
	BioMed Realty Trust	191,006,788			97.3	%		190,676,428			97.3	%
	Noncontrolling interest consisting of:
	Operating partnership and LTIP units held by employees and related parties	2,645,888			1.4	%		2,656,388			1.4	%
	Operating partnership and LTIP units held by third parties	2,627,145			1.3	%		2,627,145			1.3	%
	Total	196,279,821			100	%		195,959,961			100	%

Capital_of_the_Operating_Partn

Capital of the Operating Partnership	3 Months Ended
	Mar. 31, 2014
Partners' Capital [Abstract]	'
Capital of the Operating Partnership	'
	Capital of the Operating Partnership
	Operating Partnership Units and LTIP Units
	As of March 31, 2014, the Operating Partnership had outstanding 197,586,365 operating partnership units and 322,074 LTIP units. The Parent Company owned 97.3% of the partnership interests in the Operating Partnership at March 31, 2014, is the Operating Partnership’s general partner and is responsible for the management of the Operating Partnership’s business. As the general partner of the Operating Partnership, the Parent Company effectively controls the ability to issue common stock of the Parent Company upon a limited partner’s notice of redemption. In addition, the Parent Company has generally acquired OP units upon a limited partner’s notice of redemption in exchange for shares of its common stock. The redemption provisions of OP units owned by limited partners that permit the Parent Company to settle in either cash or common stock at the option of the Parent Company are further evaluated in accordance with applicable accounting guidance to determine whether temporary or permanent equity classification on the balance sheet is appropriate. The Operating Partnership evaluated this guidance, including the requirement to settle in unregistered shares, and determined that these OP units meet the requirements to qualify for presentation as permanent equity.
	The redemption value of the OP units owned by the limited partners, not including the Parent Company, had such units been redeemed at March 31, 2014, was approximately $109 million based on the average closing price of the Parent Company’s common stock of $20.16 per share for the ten consecutive trading days immediately preceding March 31, 2014.
	Changes in Accumulated Other Comprehensive Loss by Component
	The following table shows the changes in accumulated other comprehensive loss for the Operating Partnership for the three months ended March 31, 2014, by component (in thousands):
		Foreign currency translation adjustments		Unrealized gains on available- for-sale securities			Gain / (loss) on derivative instruments			Total
	Balance at December 31, 2013	$	4,006	$	9,186		$	(43,855	)	$	(30,663	)
	Other comprehensive income / (loss) before reclassifications	238		24,634			$	(1,449	)	23,423
	Amounts reclassified from accumulated other comprehensive income (1)	—		(9,322		)	$	2,550		(6,772		)
	Net other comprehensive income	238		15,312			1,101			16,651
	Net other comprehensive income allocable to noncontrolling interest	$	—	$	(3,344	)	$	—		$	(3,344	)
	Balance as of March 31, 2014	$	4,244	$	21,154		$	(42,754	)	$	(17,356	)
	-1	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.

Debt

Debt	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt Disclosure	'
	Debt
	Debt of the Parent Company
	The Parent Company does not hold any indebtedness. All debt is held directly or indirectly by the Operating Partnership; however, the Parent Company has guaranteed the Operating Partnership’s mortgage loan secured by the Company’s Center for Life Science | Boston property, Exchangeable Senior Notes due 2030 (the “Exchangeable Senior Notes”), Unsecured Senior Notes due 2016 (the “Notes due 2016”), Unsecured Senior Notes due 2020 (the “Notes due 2020”), Unsecured Senior Notes due 2022 (the “Notes due 2022”), Unsecured Senior Term Loan due 2017 (the “Term Loan due 2017”), Unsecured Senior Term Loan due 2018 (the “Term Loan due 2018”) and unsecured line of credit. On April 1, 2014, the Operating Partnership repaid in full the mortgage loan secured by the Company’s Center for Life Science | Boston property prior to its scheduled maturity date. The Parent Company has also guaranteed the Operating Partnership’s Unsecured Senior Notes due 2019 (the “Notes due 2019”), which were issued on April 23, 2014.
	Debt of the Operating Partnership
	The following is a summary of the Operating Partnership’s outstanding consolidated debt as of March 31, 2014 and December 31, 2013 (dollars in thousands):
		Stated Interest Rate		Effective Interest Rate		Principal Balance
						March 31,			December 31,			Maturity Date
						2014			2013
	Mortgage Notes Payable
	9900 Belward Campus Drive	5.64	%	3.99	%	$	10,593		$	10,631		July 1, 2017
	9901 Belward Campus Drive	5.64	%	3.99	%	13,045			13,091			July 1, 2017
	Center for Life Science | Boston (1)	7.75	%	7.75	%	333,398			334,447			June 30, 2014
	4320 Forest Park Avenue	4	%	2.7	%	21,000			21,000			June 30, 2015
	Hershey Center for Applied Research	6.15	%	4.71	%	13,328			13,449			May 5, 2027
	500 Kendall Street (Kendall D)	6.38	%	5.45	%	57,346			57,927			December 1, 2018
	Shady Grove Road	5.97	%	5.97	%	142,564			143,067			September 1, 2016
	University of Maryland BioPark I	5.93	%	4.69	%	16,587			16,752			May 15, 2025
	University of Maryland BioPark II	5.2	%	4.33	%	62,691			62,946			September 5, 2021
	University of Maryland BioPark Garage	5.2	%	4.33	%	4,719			4,738			September 1, 2021
	University of Miami Life Science & Technology Park	4	%	2.89	%	20,000			20,000			February 1, 2016
						695,271			698,048
	Unamortized premiums					10,742			11,276
	Mortgage notes payable, net					706,013			709,324
	Exchangeable Senior Notes	3.75	%	3.75	%	180,000			180,000			January 15, 2030
	Notes due 2016	3.85	%	3.99	%	400,000			400,000			April 15, 2016
	Notes due 2020	6.13	%	6.27	%	250,000			250,000			April 15, 2020
	Notes due 2022	4.25	%	4.36	%	250,000			250,000			July 15, 2022
						900,000			900,000
	Unamortized discounts					(4,688		)	(4,917		)
	Unsecured senior notes, net					895,312			895,083
	Term Loan due 2017 - U.S. dollar (2)	1.8	%	2.63	%	243,596			243,596			March 30, 2017
	Term Loan due 2017 - GBP (2)	2.13	%	2.39	%	166,470			165,190			March 30, 2017
	Term Loan due 2018	1.65	%	1.97	%	350,000			350,000			March 24, 2018
	Unsecured senior term loans					760,066			758,786
	Unsecured line of credit (3)	1.45	%	1.45	%	226,000			128,000			March 24, 2018
	Total consolidated debt					$	2,767,391		$	2,671,193
	-1	On April 1, 2014, the Operating Partnership repaid in full the mortgage loan secured by the Company’s Center for Life Science | Boston property prior to its scheduled maturity date.
	-2	In August 2012, the Operating Partnership converted approximately $156.4 million of outstanding borrowings into British pounds sterling (“GBP”) equal to £100.0 million, which was designated as a net investment hedge to mitigate the risk of fluctuations in foreign currency exchange rates. The principal balance represents the U.S. dollar amount based on the exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively. The effective interest rate includes the impact of interest rate swap agreements (see Note 9 for further discussion of interest rate swap agreements).
	-3	At March 31, 2014, the Operating Partnership had additional borrowing capacity under the unsecured line of credit of up to approximately $674.0 million.
	Exchangeable Senior Notes
	The exchange rate for the Exchangeable Senior Notes may be adjusted under certain circumstances, including the payment of cash dividends in excess of $0.14 per share of common stock. The increase in the quarterly cash dividend through the first quarter of 2014 resulted in an increase in the exchange rate of the Exchangeable Senior Notes to 58.4745 shares per $1,000 principal amount of Exchangeable Senior Notes (effective conversion value of $17.10 per share), as of March 27, 2014, the Company’s ex-dividend date.
	Net Investment Hedge
	The Operating Partnership designated the GBP denominated debt under the Term Loan due 2017 as a net investment hedge. The Operating Partnership entered into this net investment hedge to protect a designated amount of the Operating Partnership’s net investment in a GBP functional currency subsidiary against the risk of adverse changes in the GBP/U.S. dollar exchange rate (foreign exchange risk). Variability in the GBP/U.S. dollar exchange rate impacts the Operating Partnership (a U.S. dollar functional currency entity) as the financial statements of the GBP functional currency subsidiary are translated each period, with the effect of changes in the GBP/U.S. dollar exchange rate being recorded in accumulated other comprehensive income. When the net investment is sold or substantially liquidated, the balance of the translation adjustment accumulated in other comprehensive income will be reclassified into earnings. The Operating Partnership is hedging the risk of changes in the U.S. dollar equivalent value of a portion of its net investment in its GBP subsidiary attributable to changes in the GBP/U.S. dollar exchange rate during the period of investment during which the hedging instrument is outstanding.
	Maturities of Long-Term Debt
	As of March 31, 2014, principal payments due for the Operating Partnership’s consolidated indebtedness (excluding debt premiums and discounts) were as follows (in thousands):
	2014	$	338,639
	2015	30,006
	2016	566,516
	2017	440,360
	2018	621,663
	Thereafter (1)	764,153
		$	2,761,337
	-1	Includes $180.0 million in principal payments of the Exchangeable Senior Notes based on a contractual maturity date of January 15, 2030.
	Assumed Debts
	On April 4, 2014, the Company completed an investment in two properties, 300 George Street and 100 College Street, in New Haven, Connecticut. In connection with that investment, the Operating Partnership assumed a $46.3 million mortgage note secured by the 300 George Street property and a construction loan with $21.7 million of outstanding borrowings that were used to partially fund the development of the 100 College Street property.
	Notes due 2019
	On April 23, 2014, the Operating Partnership issued $400 million aggregate principal amount of its Notes due 2019. The Notes due 2019 are senior unsecured obligations of the Operating Partnership and rank equally in right of payment with all other senior unsecured indebtedness of the Operating Partnership. However, the Notes due 2019 are effectively subordinated to the Operating Partnership's existing and future mortgages and other secured indebtedness (to the extent of the value of the collateral securing such indebtedness) and to all existing and future preferred equity and liabilities, whether secured or unsecured, of the Operating Partnership's subsidiaries, including guarantees provided by the Operating Partnership's subsidiaries under the credit agreement governing the Operating Partnership's unsecured line of credit and Term Loan due 2018. The Notes due 2019 bear interest at 2.625% per annum, priced at 99.408% of the principal amount to yield 2.752% to maturity. Interest is payable on May 1 and November 1 of each year beginning November 1, 2014 until the maturity date of May 1, 2019. The Operating Partnership’s obligations under the Notes due 2019 are fully and unconditionally guaranteed by the Parent Company.

Earnings_Per_Share_of_the_Pare

Earnings Per Share of the Parent Company	3 Months Ended
	Mar. 31, 2014
Earnings Per Share, Basic and Diluted [Abstract]	'
Earnings Per Share of the Parent Company	'
	Earnings Per Share of the Parent Company
	Through March 31, 2014 all of the Company’s participating securities (including the OP units) received dividends/distributions at an equal dividend/distribution rate per share/unit. As a result, the portion of net income allocable to the weighted-average unvested restricted stock outstanding for the three months ended March 31, 2014 and 2013 has been deducted from net income available to common stockholders to calculate basic earnings per share. The calculation of diluted earnings per share for the three months ended March 31, 2014 and 2013 includes the outstanding OP units (both vested and unvested) in the weighted-average shares, and net income attributable to noncontrolling interests in the Operating Partnership has been added back to net income available to common stockholders. For the three months ended March 31, 2014, the Performance Units were dilutive to the calculation of diluted earnings per share as calculated, assuming that March 31, 2014 was the end date of the Performance Units' Performance Period. For the three months ended March 31, 2013, the Performance Units were dilutive to the calculation of diluted earnings per share as calculated, assuming that March 31, 2013 was the end date of the Performance Units' Performance Period. For the three months ended March 31, 2014 and 2013, the unvested restricted stock was anti-dilutive to the calculation of diluted earnings per share and was therefore excluded. As a result, diluted earnings per share was calculated based upon net income available to common stockholders less net income allocable to unvested restricted stock and distributions in excess of earnings attributable to unvested restricted stock. In addition, 10,525,410 and 10,259,496 shares issuable upon settlement of the exchange feature of the Exchangeable Senior Notes were anti-dilutive and were not included in the calculation of diluted earnings per share based on the “if converted” method for the three months ended March 31, 2014 and 2013, respectively. No other shares were considered anti-dilutive for the three months ended March 31, 2014 or 2013.
	Computations of basic and diluted earnings per share (in thousands, except share data) were as follows:
		Three Months Ended
		March 31,
		2014			2013
	Basic earnings per share:
	Net income	$	20,767		$	17,458
	Net income attributable to noncontrolling interests	(1,934		)	(146		)
	Preferred stock dividends	—			(2,393		)
	Cost on redemption of preferred stock	—			(6,531		)
	Net income allocable and distributions in excess of earnings to participating securities	(378		)	(345		)
	Net income available to common stockholders - basic	$	18,455		$	8,043
	Diluted earnings per share:
	Net income available to common stockholders - basic	18,455			8,043
	Net income attributable to noncontrolling interests in Operating Partnership	521			159
	Net income available to common stockholders - diluted	$	18,976		$	8,202
	Weighted-average common shares outstanding:
	Basic	190,905,867			159,692,470
	Incremental shares from:
	Performance units	229,295			97,788
	Operating partnership and LTIP units	5,410,374			2,923,419
	Diluted	196,545,536			162,713,677
	Basic and diluted earnings per share:
	Net income per share available to common stockholders - basic and diluted	$	0.1		$	0.05

Earnings_Per_Unit_of_the_Opera

Earnings Per Unit of the Operating Partnership	3 Months Ended
	Mar. 31, 2014
Partnership Income [Abstract]	'
Earnings Per Unit of the Operating Partnership	'
	Earnings Per Unit of the Operating Partnership
	Through March 31, 2014, all of the Operating Partnership’s participating securities received distributions at an equal distribution rate per unit. As a result, the portion of net income allocable to the weighted-average unvested OP units outstanding for the three months ended March 31, 2014 and 2013, has been deducted from net income available to unitholders to calculate basic earnings per unit. For the three months ended March 31, 2014 and 2013, the unvested OP units were anti-dilutive to the calculation of earnings per unit and were therefore excluded from the calculation of diluted earnings per unit, and diluted earnings per unit was calculated based upon net income attributable to unitholders. For the three months ended March 31, 2014, the Performance Units were dilutive to the calculation of diluted earnings per unit as calculated, assuming that March 31, 2014 was the end date of the Performance Units’ Performance Period. For the three months ended March 31, 2013, the Performance Units were dilutive to the calculation of diluted earnings per unit as calculated, assuming that March 31, 2013 was the end date of the Performance Units' Performance Period. In addition, 10,525,410 and 10,259,496 units issuable upon settlement of the exchange feature of the Exchangeable Senior Notes were anti-dilutive and were not included in the calculation of diluted earnings per unit based on the “if converted” method for the three months ended March 31, 2014 and 2013, respectively. No other units were considered anti-dilutive for the three months ended March 31, 2014 or 2013.
	Computations of basic and diluted earnings per unit (in thousands, except unit data) were as follows:
		Three Months Ended
		March 31,
		2014			2013
	Basic and diluted earnings per unit:
	Net income	$	20,767		$	17,458
	(Income) / loss attributable to noncontrolling interests	(1,413		)	8
	Preferred unit distributions	—			(2,393		)
	Cost on redemption of preferred units	—			(6,531		)
	Net income allocable and distributions in excess of earnings to participating securities	(378		)	(345		)
	Net income available to unitholders - basic and diluted	$	18,976		$	8,197
	Weighted-average units outstanding:
	Basic	196,316,241			162,612,998
	Incremental units from:
	Performance units	229,295			97,788
	Diluted	196,545,536			162,710,786
	Basic and diluted earnings per unit:
	Net income per unit available to unitholders - basic and diluted	$	0.1		$	0.05

Investment_in_Unconsolidated_P

Investment in Unconsolidated Partnerships	3 Months Ended
	Mar. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Investment in Unconsolidated Partnerships	'
	Investment in Unconsolidated Partnerships
	The accompanying consolidated financial statements include investments in two limited liability companies with Prudential Real Estate Investors (“PREI”), 10165 McKellar Court, L.P. (“McKellar Court”), a limited partnership with Quidel Corporation, the tenant which occupies the McKellar Court property and BioPark Fremont, LLC ("BioPark Fremont"), a limited liability company with RPC Poppleton, LLC. General information on the PREI limited liability companies, the McKellar Court partnership and BioPark Fremont (each referred to in this footnote individually as a “partnership” and collectively as the “partnerships”) as of March 31, 2014 was as follows:
	Name	Partner		Company’s		Company’s		Date Acquired
				Ownership		Economic
				Interest		Interest
	PREI I LLC (1)	PREI		20%		20%		April 4, 2007
	PREI II LLC	PREI		20%		20%		April 4, 2007
	McKellar Court (2)	Quidel Corporation		22%		22%		September 30, 2004
	BioPark Fremont	RPC Poppleton, LLC		50%		50%		May 31, 2013
	-1	PREI I LLC owns two properties in Cambridge, Massachusetts. At March 31, 2014, there were $139.0 million in outstanding borrowings on a secured loan facility held by a wholly-owned subsidiary of PREI I LLC, with a contractual interest rate of 3.16% (including the applicable credit spread) and a maturity date of August 13, 2014. At maturity, PREI I LLC may refinance the secured loan facility, depending on market conditions and the availability of credit, or it may repay the principal balance through capital contributions of its members.
	-2	The Company’s investment in the McKellar Court partnership (maximum exposure to losses) was approximately $12.0 million at March 31, 2014. The Company’s economic interest in the McKellar Court partnership entitles it to 75% of the extraordinary cash flows after repayment of the partners’ capital contributions and 22% of the operating cash flows.
	The condensed combined balance sheets for all of the Company’s unconsolidated partnerships were as follows (in thousands):
		March 31,				December 31,
		2014				2013
	Assets:
	Investments in real estate, net	$	271,132			$	262,753
	Cash and cash equivalents (including restricted cash)	5,612				3,855
	Other assets	3,758				5,301
	Total assets	$	280,502			$	271,909
	Liabilities and members’ equity:
	Mortgage notes payable and secured loan	$	151,992			$	151,968
	Other liabilities	23,541				12,102
	Members’ equity	104,969				107,839
	Total liabilities and members equity	$	280,502			$	271,909
	Company’s net investment in unconsolidated partnerships	$	31,461			$	32,137
	The selected data and results of operations for the unconsolidated partnerships were as follows (in thousands):
			Three Months Ended
			March 31,
			2014				2013
	Total revenues		$	4,059			$	2,830
	Total expenses		(6,130		)		(5,448		)
	Net loss		(2,071		)		(2,618		)
	Company’s equity in net loss of unconsolidated partnerships		$	(138	)		$	(319	)
	Fees earned by the Company (1)		$	283			$	22
	-1	The Company acts as the operating member or partner, as applicable, and day-to-day manager for the partnerships. The Company is entitled to receive fees for providing construction and development services (as applicable) and management services to the PREI joint ventures, which are reflected in tenant recoveries and other income in the consolidated statements of income.

Derivatives_and_Other_Financia

Derivatives and Other Financial Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivatives and Other Financial Instruments	'
	Derivatives and Other Financial Instruments
	The Company is exposed to the effect of changes in interest rates on the Operating Partnership’s U.S. dollar-LIBOR-based and GBP-LIBOR-based debt. The Company limits this risk by following established risk management policies and procedures including the use of derivatives. The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements related to the Operating Partnership’s LIBOR-based debt. To accomplish these objectives, the Company primarily uses interest rate swaps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. The interest rate swaps hedge the Company’s exposure to the variability on expected cash flows attributable to changes in interest rates. These interest rate swaps are currently intended to hedge interest payments associated with the Operating Partnership’s Term Loan due 2017 and Term Loan due 2018.
	As of March 31, 2014, the Company had deferred interest costs of approximately $33.7 million in accumulated other comprehensive loss related to forward starting swaps, which were settled with the corresponding counterparties in 2009. The forward starting swaps were entered into to mitigate the Company’s exposure to the variability in expected future cash flows attributable to changes in future interest rates associated with a forecasted issuance of fixed-rate debt, with interest payments for a minimum of ten years. The deferred interest costs will be amortized as additional interest expense over a remaining period of approximately five years.
	The following is a summary of the terms of the interest rate swaps, other derivatives and their respective fair-values (dollars in thousands):
											Fair-Value(1)
		Notional Amount									March 31,			December 31,
						Strike Rate			Effective Date	Expiration Date	2014			2013
	Interest rate swaps	$	200,000			1.163	%		March 30, 2012	March 30, 2017	$	(1,814	)	$	(1,876	)
	Interest rate swaps	200,000				0.701	%		October 1, 2013	October 1, 2016	(341		)	(288		)
	Interest rate swaps(2)	83,235				0.731	%		August 2, 2012	March 30, 2017	1,288			1,545
	Interest rate swaps(2)	83,235				0.7425	%		August 2, 2012	March 30, 2017	1,261			1,519
	Total interest rate swaps	$	566,470								394			900
	Other derivatives										578			416
	Total										$	972		$	1,316
	-1	Fair-value of derivative instruments does not include any related accrued interest payable, which is included in accrued expenses on the accompanying consolidated balance sheets. Derivative valuations are classified in Level 2 of the fair-value hierarchy. Assets are included in other assets and liabilities are included in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets.
	-2	Translations to U.S. dollars are based on exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively.
	For derivatives designated as cash flow hedges, the effective portion of changes in the fair-value of the derivative is initially reported in other comprehensive income (outside of earnings) and subsequently reclassified to earnings in the period in which the hedged forecasted transaction affects earnings. During the three months ended March 31, 2014 and 2013, such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt. The ineffective portion of the change in fair-value of the derivatives is recognized directly in earnings. No portion of the derivatives designated as cash flow hedges were classified as ineffective during the three months ended March 31, 2014 and 2013.
	The following is a summary of the amount of loss recognized in other comprehensive income related to the derivative instruments (in thousands):
			Three Months Ended
			March 31,
			2014				2013
	Amount of loss recognized in other comprehensive income (effective portion):
	Cash flow hedges
	Interest rate swaps		$	(1,449	)		$	(697	)
	Amount of loss reclassified from accumulated other comprehensive loss to earnings(effective portion):
	Cash flow hedges
	Interest rate swaps (1)		$	859			$	560
	Forward starting swaps (2)		1,691				1,718
	Total interest rate swaps		$	2,550			$	2,278
	-1	Amount represents payments made to swap counterparties for the effective portion of interest rate swaps that were recognized as an increase to interest expense for the periods presented (the amount was recorded as an increase and corresponding decrease to accumulated other comprehensive loss in the same accounting period).
	-2	Amount represents reclassifications of deferred interest costs from accumulated other comprehensive loss to interest expense related to the Company’s previously settled forward starting swaps.
	During the next twelve months, the Company estimates that an additional $10.1 million will be reclassified from accumulated other comprehensive loss as an increase to interest expense.
	During the three months ended March 31, 2014, the Company recorded total unrealized gain on derivative instruments of $162,000 related to changes in the fair-value of other derivative instruments, included in other income, net in the consolidated statements of income.

FairValue_of_Financial_Instrum

Fair-Value of Financial Instruments	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Disclosures	'
	Fair-Value of Financial Instruments
	The Company’s disclosures of estimated fair-value of financial instruments at March 31, 2014 and December 31, 2013 were determined using available market information and appropriate valuation methods. Considerable judgment is necessary to interpret market data and develop estimated fair-value. The use of different market assumptions or estimation methods may have a material effect on the estimated fair-value amounts.
	The carrying amounts for cash and cash equivalents, accounts receivable, accounts payable, accrued expenses and other liabilities approximate fair-value due to the short-term nature of these instruments.
	The Company utilizes quoted market prices to estimate the fair-value of its fixed-rate and variable-rate debt, when available. If quoted market prices are not available, the Company calculates the fair-value of its mortgage notes payable and other fixed-rate debt based on a currently available market rate assuming the loans are outstanding through maturity and considering the collateral. In determining the current market rate for fixed-rate debt, a market credit spread is added to the quoted yields on federal government treasury securities with similar terms to debt. In determining the current market rate for variable-rate debt, a market credit spread is added to the current effective interest rate. The carrying values of interest rate swaps are reflected at their fair-values.
	At March 31, 2014 and December 31, 2013, the aggregate fair-value and the carrying value of the Company’s financial instruments were as follows (in thousands):
		March 31, 2014						December 31, 2013
		Fair-Value (1)			Carrying Value			Fair-Value (1)			Carrying Value
	Mortgage notes payable, net	$	717,511		$	706,013		$	730,394		$	709,324
	Exchangeable Senior Notes	216,000			180,000			202,626			180,000
	Notes due 2016, net	419,792			398,912			417,040			398,787
	Notes due 2020, net	280,473			248,268			275,600			248,210
	Notes due 2022, net	247,903			248,132			240,400			248,086
	Term Loan due 2017 - U.S. dollar	244,664			243,596			244,751			243,596
	Term Loan due 2017 - GBP (2)	167,197			166,470			165,969			165,190
	Term Loan due 2018	350,000			350,000			350,000			350,000
	Unsecured line of credit	226,000			226,000			128,000			128,000
	Derivative instruments (3)	(972		)	(972		)	(1,316		)	(1,316		)
	Available-for-sale securities	33,279			33,279			19,566			19,566
	-1	Fair-values of debt and derivative instruments are classified in Level 2 of the fair-value hierarchy. Fair-value of available-for-sale securities are classified in Level 1 of the fair-value hierarchy.
	-2	The principal balance represents the U.S. dollar amount based on the exchange rate of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively.
	-3	The Company’s derivative instruments are reflected in other assets and in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets based on their respective balances (see Note 9).

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Principles of Consolidation	'
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, partnerships and limited liability companies it controls, and variable interest entities (“VIEs”) for which the Company has determined itself to be the primary beneficiary. All material intercompany transactions and balances have been eliminated. The Company consolidates entities the Company controls and records a noncontrolling interest for the portions not owned by the Company. Control is determined, where applicable, by the sufficiency of equity invested and the rights of the equity holders, and by the ownership of a majority of the voting interests, with consideration given to the existence of approval or veto rights granted to the minority stockholder. If the minority stockholder holds substantive participating rights, it overcomes the presumption of control by the majority voting interest holder. In contrast, if the minority stockholder simply holds protective rights (such as consent rights over certain actions), it does not overcome the presumption of control by the majority voting interest holder.
	Assets and liabilities of subsidiaries outside the United States with non-U.S. dollar functional currencies are translated into U.S. dollars using exchange rates as of the balance sheet dates. Income and expenses are translated using the average exchange rates for the reporting period. Foreign currency translation adjustments are recorded as a component of other comprehensive income. For the three months ended March 31, 2014 and 2013, total revenues from properties outside the United States were $4.8 million and $4.5 million, respectively, which represented 2.8% of the Company's total revenues during each period. The Company’s net investments in properties outside the United States were $190.7 million and $190.2 million at March 31, 2014 and December 31, 2013, respectively.
Investments in Partnerships and Limited Liability Companies	'
	Investments in Partnerships and Limited Liability Companies
	The Company has determined that it is the primary beneficiary in five VIEs (excluding certain VIEs through its ownership of Wexford), consisting of single-tenant properties in which the tenant has a fixed-price purchase option, which are consolidated and reflected in the accompanying consolidated financial statements. Selected financial data of these VIEs at March 31, 2014 and December 31, 2013 consist of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	339,284		$	336,832
	Total assets	378,961			375,443
	Total debt	142,564			143,067
	Total liabilities	156,186			154,953
	Wexford - Variable Interest Entities
	Wexford is a party to certain contractual arrangements with tax credit investors (“TCIs”) that were established to enable the TCIs to receive the benefits of historic tax credits (“HTCs”) and/or new market tax credits (“NMTCs”) for certain properties owned by Wexford. At March 31, 2014, Wexford owned nine properties that had syndicated HTCs or NMTCs, or both, to TCIs.
	Historic Tax Credits and New Market Tax Credits
	Capital contributions are made by TCIs into special purpose entities that ultimately invest these funds in the entity that owns the subject property that generates the tax credits. The TCIs are allocated substantially all of the tax credits and hold only a noncontrolling interest in the economic risk and rewards of the special purpose entities. HTCs are delivered to the TCI upon substantial completion of the project. NMTCs are allowed for up to 39% of a qualified investment and are delivered to the TCI after the investment has been funded and spent on a qualified business. HTCs are subject to 20% recapture per year beginning one year after the completion of the historic rehabilitation of the subject property. NMTCs are subject to 100% recapture until the end of the seventh year following the qualifying investment. The Company has provided the TCIs with certain guarantees which protect the TCIs from loss should a tax credit recapture event occur. The contractual arrangements with the TCIs include a put/call provision whereby the Company may be obligated or entitled to repurchase the ownership interest of the TCIs in the special purpose entities at the end of the tax credit recapture period. The Company anticipates that either the TCIs will exercise their put rights or the Company will exercise its call rights; however, the Company believes that the put rights are more likely to be exercised.
	The Company has determined that the special purpose entities are VIEs, since there is insufficient capital to finance their activities without further subordinated financial support. The Company has determined that it is the primary beneficiary of these VIEs, because it has the authority to direct the activities which most significantly impact their economic performance.
	The portion of the TCI’s capital contribution that is attributed to the put is recorded at fair-value at inception and is accreted to the expected put price as interest expense in the consolidated statement of income. At March 31, 2014, approximately $4.5 million of put liabilities were included in other liabilities in the consolidated balance sheets. The remaining balance of the TCI’s capital contribution is initially recorded in other liabilities in the consolidated balance sheets and is reclassified, upon delivery of the tax credit to the TCI, to reduce the carrying value of the subject property, net of allocated expenses. Direct and incremental costs incurred in structuring the transaction, consisting of third-party legal, accounting and other professional fees are deferred and will be recognized as an increase in the cost basis of the subject property upon the recognition of the related tax credit as discussed above. During the quarter ended March 31, 2014, $15.5 million of tax credits, net of costs and estimated put payments, were contributed by TCIs and recorded as other liabilities in the consolidated balance sheets, of which $12.8 million in tax credits were delivered to the TCIs and reclassified as a reduction of the carrying value of the subject property.
	The Company has determined that certain special purpose entities owning properties under development are VIEs, since there is insufficient capital to finance the remaining development activities without further subordinated financial support. The Company has determined it is the primary beneficiary of these VIEs, because it has the authority to direct the activities which most significantly impact their economic performance. Selected financial data of the VIEs at March 31, 2014 consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	181,458		$	177,901
	Total assets	193,789			198,968
	Total liabilities	63,877			60,197
Investments in Real Estate, Net	'
	Investments in Real Estate, Net
	Investments in real estate, net consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Land	$	717,328		$	713,955
	Land under development	116,220			119,325
	Buildings and improvements	4,907,630			4,854,175
	Construction in progress	329,803			316,025
		6,070,981			6,003,480
	Accumulated depreciation	(835,945		)	(785,578		)
		$	5,235,036		$	5,217,902
Impairment of Long-Lived Assets and Long-Lived Assets to be Disposed	'
	Impairment of Long-Lived Assets and Long-Lived Assets to be Disposed
	The Company reviews long-lived assets and certain identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The review of recoverability is based on an estimate of the future undiscounted cash flows (excluding interest charges) expected to result from the long-lived asset’s use and eventual disposition. These cash flows consider factors such as expected future operating income, trends and prospects, as well as the effects of leasing demand, competition and other factors. If impairment exists due to the inability to recover the carrying value of a long-lived asset, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair-value of the property. The Company is required to make subjective assessments as to whether there are impairments in the values of its investments in long-lived assets. These assessments have a direct impact on the Company’s net income because recording an impairment loss results in an immediate negative adjustment to net income. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Although the Company’s strategy is to hold its properties over the long-term, if the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized to reduce the property to the lower of the carrying amount or fair-value, and such loss could be material. As of and for the three months ended March 31, 2014, no assets have been identified as impaired and no such impairment losses have been recognized.
Deferred Leasing Costs, Net	'
	Deferred Leasing Costs, Net
	Leasing commissions and other direct costs associated with obtaining new or renewal leases are recorded at cost and amortized on a straight-line basis over the terms of the respective leases, with remaining terms ranging from less than one year to approximately 20 years as of March 31, 2014. Deferred leasing costs also include the net carrying value of acquired in-place leases and acquired management agreements.
	Deferred leasing costs, net at March 31, 2014 consisted of the following (in thousands):
		Balance at			Accumulated
		March 31, 2014			Amortization			Net
	Acquired in-place leases	$	365,944		$	(243,437	)	$	122,507
	Acquired management agreements	25,801			(20,502		)	5,299
	Deferred leasing and other direct costs	94,273			(32,552		)	61,721
		$	486,018		$	(296,491	)	$	189,527
	Deferred leasing costs, net at December 31, 2013 consisted of the following (in thousands):
		Balance at			Accumulated
		December 31, 2013			Amortization			Net
	Acquired in-place leases	$	365,753		$	(233,935	)	$	131,818
	Acquired management agreements	25,801			(20,053		)	5,748
	Deferred leasing and other direct costs	91,142			(30,641		)	60,501
		$	482,696		$	(284,629	)	$	198,067
Investments	'
	Investments
	Investments in equity securities, which are included in other assets on the accompanying consolidated balance sheets, consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Available-for-sale securities, historical cost	$	7,191		$	8,543
	Unrealized gain, net	26,088			11,023
	Available-for-sale securities, fair-value (1)	33,279			19,566
	Privately-held securities, cost basis	17,107			18,485
	Total equity securities	$	50,386		$	38,051
	-1	Determination of fair-value is classified as Level 1 in the fair-value hierarchy based on the use of quoted prices in active markets.
	The Company holds investments in available-for-sale securities of certain publicly-traded companies. Certain of these investments have fair-values less than the Company’s cost basis, net of previous other-than-temporary impairment in these securities due to decreases in their respective stock prices during the three months ended March 31, 2014. However, management has the intent and ability to retain the investments for a period of time sufficient to allow for an anticipated recovery in their market value. Management will continue to periodically evaluate whether any investment, the fair-value of which is less than the Company’s cost basis, should be considered other-than-temporarily impaired. If other-than-temporary impairment is considered to exist, the related unrealized loss will be reclassified from accumulated other comprehensive loss and recorded as a reduction of net income.
	The Company also holds investments in securities of certain privately-held companies and funds, which are recorded at cost basis due to the Company’s lack of control or significant influence over such companies and funds.
	During the three months ended March 31, 2014, the Company recorded a $1.3 million impairment charge, which is included in other expense in the consolidated statements of income. The impairment charge related to the Company’s investment in a privately-held company. Other than this investment there were no identified events or changes in circumstances that may have a significant adverse effect on the carrying value of the Company’s cost basis investments and therefore, no evaluation of impairment was performed during the three months ended March 31, 2014 on the Company’s remaining cost basis investments.
Construction Loan Receivable	'
	Construction Loan Receivable
	The Company has a $255.0 million interest in a $355.0 million construction loan secured by first priority mortgages on a 1.1 million square foot laboratory, office and retail development project located in Boston, Massachusetts, which is 95% leased to Vertex Pharmaceuticals Incorporated to serve as its new corporate headquarters (the "Construction Loan").
	The Construction Loan matures on September 30, 2014, with two one -year extension options exercisable at the borrower’s election after paying the lenders an extension fee on the then-outstanding principal amount. The Construction Loan bears interest on the outstanding principal amount at a floating rate equal to the greater of (1) reserve adjusted LIBOR plus 550 basis points and (2) 6.5%. In addition, the borrower is required to pay a fee to the lenders based on a specified percentage of the average daily unfunded amount of the Construction Loan. The borrower may prepay the Construction Loan in part under certain circumstances, and may prepay the Construction Loan in full with prior notice and a prepayment fee to the lenders. As of March 31, 2014 and December 31, 2013, the Company had invested approximately $191.3 million and $151.8 million, respectively, in the Construction Loan, which are included in other assets on the Company's consolidated balance sheets.
Lease Termination	'
	Lease Termination
	During the three months ended March 31, 2014 and 2013, the Company recorded lease termination revenue, net of write-offs of lease intangibles, included in other revenue on the consolidated statement of income of approximately $5.5 million and $24.0 million, respectively. Lease termination revenue for the three months ended March 31, 2014 primarily related to the early termination of leases at the Company's 4570 Executive Drive property. Lease termination revenue for the three months ended March 31, 2013 primarily related to the termination of a lease with Elan Corporation at the Company’s Science Center at Oyster Point property for which Elan paid the Company $46.5 million
Management's Estimates	'
	Management’s Estimates
	Management has made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reporting of revenue and expenses during the reporting period to prepare these consolidated financial statements in conformity with GAAP. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and reported amounts of revenue and expenses that are not readily apparent from other sources. Actual results could differ from those estimates under different assumptions or conditions.

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Selected Financial Data of the VIEs	'
	Selected financial data of these VIEs at March 31, 2014 and December 31, 2013 consist of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	339,284		$	336,832
	Total assets	378,961			375,443
	Total debt	142,564			143,067
	Total liabilities	156,186			154,953
	The Company has determined that certain special purpose entities owning properties under development are VIEs, since there is insufficient capital to finance the remaining development activities without further subordinated financial support. The Company has determined it is the primary beneficiary of these VIEs, because it has the authority to direct the activities which most significantly impact their economic performance. Selected financial data of the VIEs at March 31, 2014 consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Investment in real estate, net	$	181,458		$	177,901
	Total assets	193,789			198,968
	Total liabilities	63,877			60,197
Investments in Real Estate, Net	'
	Investments in real estate, net consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Land	$	717,328		$	713,955
	Land under development	116,220			119,325
	Buildings and improvements	4,907,630			4,854,175
	Construction in progress	329,803			316,025
		6,070,981			6,003,480
	Accumulated depreciation	(835,945		)	(785,578		)
		$	5,235,036		$	5,217,902
Deferred Leasing Costs, Net	'
	Deferred leasing costs, net at March 31, 2014 consisted of the following (in thousands):
		Balance at			Accumulated
		March 31, 2014			Amortization			Net
	Acquired in-place leases	$	365,944		$	(243,437	)	$	122,507
	Acquired management agreements	25,801			(20,502		)	5,299
	Deferred leasing and other direct costs	94,273			(32,552		)	61,721
		$	486,018		$	(296,491	)	$	189,527
	Deferred leasing costs, net at December 31, 2013 consisted of the following (in thousands):
		Balance at			Accumulated
		December 31, 2013			Amortization			Net
	Acquired in-place leases	$	365,753		$	(233,935	)	$	131,818
	Acquired management agreements	25,801			(20,053		)	5,748
	Deferred leasing and other direct costs	91,142			(30,641		)	60,501
		$	482,696		$	(284,629	)	$	198,067
Investments in Equity Securities	'
	Investments in equity securities, which are included in other assets on the accompanying consolidated balance sheets, consisted of the following (in thousands):
		March 31,			December 31,
		2014			2013
	Available-for-sale securities, historical cost	$	7,191		$	8,543
	Unrealized gain, net	26,088			11,023
	Available-for-sale securities, fair-value (1)	33,279			19,566
	Privately-held securities, cost basis	17,107			18,485
	Total equity securities	$	50,386		$	38,051
	-1	Determination of fair-value is classified as Level 1 in the fair-value hierarchy based on the use of quoted prices in active markets.

Equity_of_the_Parent_Company_T

Equity of the Parent Company (Tables)	3 Months Ended
	Mar. 31, 2014
Equity of the Parent Company	'
Dividends and Distributions	'
	The following table lists the dividends and distributions declared by the Parent Company and the Operating Partnership during the three months ended March 31, 2014:
	Declaration Date		Securities Class		Amount Per				Period Covered		Dividend and		Dividend and
					Share/Unit						Distribution		Distribution Amount
											Payable Date
													(In thousands)
	March 17, 2014		Common stock and OP units		$	0.25			January 1, 2014 to March 31, 2014		April 15, 2014		$	49,479
Changes in Accumulated Other Comprehensive Loss by Component	'
	Changes in Accumulated Other Comprehensive Loss by Component
	The following table shows the changes in accumulated other comprehensive loss for the Operating Partnership for the three months ended March 31, 2014, by component (in thousands):
		Foreign currency translation adjustments				Unrealized gains on available- for-sale securities				Gain / (loss) on derivative instruments				Total
	Balance at December 31, 2013	$	4,006			$	9,186			$	(43,855	)		$	(30,663	)
	Other comprehensive income / (loss) before reclassifications	238				24,634				$	(1,449	)		23,423
	Amounts reclassified from accumulated other comprehensive income (1)	—				(9,322		)		$	2,550			(6,772		)
	Net other comprehensive income	238				15,312				1,101				16,651
	Net other comprehensive income allocable to noncontrolling interest	$	—			$	(3,344	)		$	—			$	(3,344	)
	Balance as of March 31, 2014	$	4,244			$	21,154			$	(42,754	)		$	(17,356	)
	-1	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.
Vested Ownership Interests	'
	The following table shows the vested ownership interests in the Operating Partnership:
		March 31, 2014						December 31, 2013
		Operating Partnership Units and LTIP Units			Percentage of Total			Operating Partnership Units and LTIP Units			Percentage of Total
	BioMed Realty Trust	191,006,788			97.3	%		190,676,428			97.3	%
	Noncontrolling interest consisting of:
	Operating partnership and LTIP units held by employees and related parties	2,645,888			1.4	%		2,656,388			1.4	%
	Operating partnership and LTIP units held by third parties	2,627,145			1.3	%		2,627,145			1.3	%
	Total	196,279,821			100	%		195,959,961			100	%
Parent Company	'
Equity of the Parent Company	'
Changes in Accumulated Other Comprehensive Loss by Component	'
	Changes in Accumulated Other Comprehensive Loss by Component
	The following table shows the changes in accumulated other comprehensive loss for the Parent Company for the three months ended March 31, 2014, by component (in thousands):
		Foreign currency translation adjustments				Unrealized gains on available-for-sale securities				Gain / (loss) on derivative instruments				Total
	Balance at December 31, 2013	$	3,905			$	8,938			$	(45,766	)		$	(32,923	)
	Other comprehensive income / (loss) before reclassifications	238				24,634				$	(1,449	)		23,423
	Amounts reclassified from accumulated other comprehensive income (1)	—				(9,322		)		$	2,550			(6,772		)
	Net other comprehensive income	238				15,312				1,101				16,651
	Net other comprehensive income allocable to noncontrolling interests	(6		)		(3,666		)		(29		)		(3,701		)
	Balance as of March 31, 2014	$	4,137			$	20,584			$	(44,694	)		$	(19,973	)
	-1	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.

Capital_of_the_Operating_Partn1

Capital of the Operating Partnership Capital of the Operating Partnership (Tables)	3 Months Ended
	Mar. 31, 2014
Statement of Partners' Capital [Abstract]	'
Changes in Accumulated Other Comprehensive Loss by Component	'
	Changes in Accumulated Other Comprehensive Loss by Component
	The following table shows the changes in accumulated other comprehensive loss for the Operating Partnership for the three months ended March 31, 2014, by component (in thousands):
		Foreign currency translation adjustments		Unrealized gains on available- for-sale securities			Gain / (loss) on derivative instruments			Total
	Balance at December 31, 2013	$	4,006	$	9,186		$	(43,855	)	$	(30,663	)
	Other comprehensive income / (loss) before reclassifications	238		24,634			$	(1,449	)	23,423
	Amounts reclassified from accumulated other comprehensive income (1)	—		(9,322		)	$	2,550		(6,772		)
	Net other comprehensive income	238		15,312			1,101			16,651
	Net other comprehensive income allocable to noncontrolling interest	$	—	$	(3,344	)	$	—		$	(3,344	)
	Balance as of March 31, 2014	$	4,244	$	21,154		$	(42,754	)	$	(17,356	)
	-1	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Summary of the Operating Partnership's Outstanding Consolidated Debt	'
	The following is a summary of the Operating Partnership’s outstanding consolidated debt as of March 31, 2014 and December 31, 2013 (dollars in thousands):
		Stated Interest Rate		Effective Interest Rate		Principal Balance
						March 31,			December 31,			Maturity Date
						2014			2013
	Mortgage Notes Payable
	9900 Belward Campus Drive	5.64	%	3.99	%	$	10,593		$	10,631		July 1, 2017
	9901 Belward Campus Drive	5.64	%	3.99	%	13,045			13,091			July 1, 2017
	Center for Life Science | Boston (1)	7.75	%	7.75	%	333,398			334,447			June 30, 2014
	4320 Forest Park Avenue	4	%	2.7	%	21,000			21,000			June 30, 2015
	Hershey Center for Applied Research	6.15	%	4.71	%	13,328			13,449			May 5, 2027
	500 Kendall Street (Kendall D)	6.38	%	5.45	%	57,346			57,927			December 1, 2018
	Shady Grove Road	5.97	%	5.97	%	142,564			143,067			September 1, 2016
	University of Maryland BioPark I	5.93	%	4.69	%	16,587			16,752			May 15, 2025
	University of Maryland BioPark II	5.2	%	4.33	%	62,691			62,946			September 5, 2021
	University of Maryland BioPark Garage	5.2	%	4.33	%	4,719			4,738			September 1, 2021
	University of Miami Life Science & Technology Park	4	%	2.89	%	20,000			20,000			February 1, 2016
						695,271			698,048
	Unamortized premiums					10,742			11,276
	Mortgage notes payable, net					706,013			709,324
	Exchangeable Senior Notes	3.75	%	3.75	%	180,000			180,000			January 15, 2030
	Notes due 2016	3.85	%	3.99	%	400,000			400,000			April 15, 2016
	Notes due 2020	6.13	%	6.27	%	250,000			250,000			April 15, 2020
	Notes due 2022	4.25	%	4.36	%	250,000			250,000			July 15, 2022
						900,000			900,000
	Unamortized discounts					(4,688		)	(4,917		)
	Unsecured senior notes, net					895,312			895,083
	Term Loan due 2017 - U.S. dollar (2)	1.8	%	2.63	%	243,596			243,596			March 30, 2017
	Term Loan due 2017 - GBP (2)	2.13	%	2.39	%	166,470			165,190			March 30, 2017
	Term Loan due 2018	1.65	%	1.97	%	350,000			350,000			March 24, 2018
	Unsecured senior term loans					760,066			758,786
	Unsecured line of credit (3)	1.45	%	1.45	%	226,000			128,000			March 24, 2018
	Total consolidated debt					$	2,767,391		$	2,671,193
	-1	On April 1, 2014, the Operating Partnership repaid in full the mortgage loan secured by the Company’s Center for Life Science | Boston property prior to its scheduled maturity date.
	-2	In August 2012, the Operating Partnership converted approximately $156.4 million of outstanding borrowings into British pounds sterling (“GBP”) equal to £100.0 million, which was designated as a net investment hedge to mitigate the risk of fluctuations in foreign currency exchange rates. The principal balance represents the U.S. dollar amount based on the exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively. The effective interest rate includes the impact of interest rate swap agreements (see Note 9 for further discussion of interest rate swap agreements).
	-3	At March 31, 2014, the Operating Partnership had additional borrowing capacity under the unsecured line of credit of up to approximately $674.0 million.
Principal Payments Due for Operating Partnership's Consolidated Indebtedness	'
	As of March 31, 2014, principal payments due for the Operating Partnership’s consolidated indebtedness (excluding debt premiums and discounts) were as follows (in thousands):
	2014	$	338,639
	2015	30,006
	2016	566,516
	2017	440,360
	2018	621,663
	Thereafter (1)	764,153
		$	2,761,337
	-1	Includes $180.0 million in principal payments of the Exchangeable Senior Notes based on a contractual maturity date of January 15, 2030.

Earnings_Per_Share_of_the_Pare1

Earnings Per Share of the Parent Company (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share, Basic and Diluted [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted	'
	Computations of basic and diluted earnings per share (in thousands, except share data) were as follows:
		Three Months Ended
		March 31,
		2014			2013
	Basic earnings per share:
	Net income	$	20,767		$	17,458
	Net income attributable to noncontrolling interests	(1,934		)	(146		)
	Preferred stock dividends	—			(2,393		)
	Cost on redemption of preferred stock	—			(6,531		)
	Net income allocable and distributions in excess of earnings to participating securities	(378		)	(345		)
	Net income available to common stockholders - basic	$	18,455		$	8,043
	Diluted earnings per share:
	Net income available to common stockholders - basic	18,455			8,043
	Net income attributable to noncontrolling interests in Operating Partnership	521			159
	Net income available to common stockholders - diluted	$	18,976		$	8,202
	Weighted-average common shares outstanding:
	Basic	190,905,867			159,692,470
	Incremental shares from:
	Performance units	229,295			97,788
	Operating partnership and LTIP units	5,410,374			2,923,419
	Diluted	196,545,536			162,713,677
	Basic and diluted earnings per share:
	Net income per share available to common stockholders - basic and diluted	$	0.1		$	0.05

Earnings_Per_Unit_of_the_Opera1

Earnings Per Unit of the Operating Partnership (Tables)	3 Months Ended
	Mar. 31, 2014
Partnership Income [Abstract]	'
Computations of Basic and Diluted Earnings Per Unit	'
	Computations of basic and diluted earnings per unit (in thousands, except unit data) were as follows:
		Three Months Ended
		March 31,
		2014			2013
	Basic and diluted earnings per unit:
	Net income	$	20,767		$	17,458
	(Income) / loss attributable to noncontrolling interests	(1,413		)	8
	Preferred unit distributions	—			(2,393		)
	Cost on redemption of preferred units	—			(6,531		)
	Net income allocable and distributions in excess of earnings to participating securities	(378		)	(345		)
	Net income available to unitholders - basic and diluted	$	18,976		$	8,197
	Weighted-average units outstanding:
	Basic	196,316,241			162,612,998
	Incremental units from:
	Performance units	229,295			97,788
	Diluted	196,545,536			162,710,786
	Basic and diluted earnings per unit:
	Net income per unit available to unitholders - basic and diluted	$	0.1		$	0.05

Investment_in_Unconsolidated_P1

Investment in Unconsolidated Partnerships (Tables)	3 Months Ended
	Mar. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Summary of Unconsolidated Partnerships	'
	The accompanying consolidated financial statements include investments in two limited liability companies with Prudential Real Estate Investors (“PREI”), 10165 McKellar Court, L.P. (“McKellar Court”), a limited partnership with Quidel Corporation, the tenant which occupies the McKellar Court property and BioPark Fremont, LLC ("BioPark Fremont"), a limited liability company with RPC Poppleton, LLC. General information on the PREI limited liability companies, the McKellar Court partnership and BioPark Fremont (each referred to in this footnote individually as a “partnership” and collectively as the “partnerships”) as of March 31, 2014 was as follows:
	Name	Partner		Company’s		Company’s		Date Acquired
				Ownership		Economic
				Interest		Interest
	PREI I LLC (1)	PREI		20%		20%		April 4, 2007
	PREI II LLC	PREI		20%		20%		April 4, 2007
	McKellar Court (2)	Quidel Corporation		22%		22%		September 30, 2004
	BioPark Fremont	RPC Poppleton, LLC		50%		50%		May 31, 2013
	-1	PREI I LLC owns two properties in Cambridge, Massachusetts. At March 31, 2014, there were $139.0 million in outstanding borrowings on a secured loan facility held by a wholly-owned subsidiary of PREI I LLC, with a contractual interest rate of 3.16% (including the applicable credit spread) and a maturity date of August 13, 2014. At maturity, PREI I LLC may refinance the secured loan facility, depending on market conditions and the availability of credit, or it may repay the principal balance through capital contributions of its members.
	-2	The Company’s investment in the McKellar Court partnership (maximum exposure to losses) was approximately $12.0 million at March 31, 2014. The Company’s economic interest in the McKellar Court partnership entitles it to 75% of the extraordinary cash flows after repayment of the partners’ capital contributions and 22% of the operating cash flows.
Summary of Selected Balance Sheet Information	'
	The condensed combined balance sheets for all of the Company’s unconsolidated partnerships were as follows (in thousands):
		March 31,				December 31,
		2014				2013
	Assets:
	Investments in real estate, net	$	271,132			$	262,753
	Cash and cash equivalents (including restricted cash)	5,612				3,855
	Other assets	3,758				5,301
	Total assets	$	280,502			$	271,909
	Liabilities and members’ equity:
	Mortgage notes payable and secured loan	$	151,992			$	151,968
	Other liabilities	23,541				12,102
	Members’ equity	104,969				107,839
	Total liabilities and members equity	$	280,502			$	271,909
	Company’s net investment in unconsolidated partnerships	$	31,461			$	32,137
Schedule of Selected Income Statement Information	'
	The selected data and results of operations for the unconsolidated partnerships were as follows (in thousands):
			Three Months Ended
			March 31,
			2014				2013
	Total revenues		$	4,059			$	2,830
	Total expenses		(6,130		)		(5,448		)
	Net loss		(2,071		)		(2,618		)
	Company’s equity in net loss of unconsolidated partnerships		$	(138	)		$	(319	)
	Fees earned by the Company (1)		$	283			$	22
	-1	The Company acts as the operating member or partner, as applicable, and day-to-day manager for the partnerships. The Company is entitled to receive fees for providing construction and development services (as applicable) and management services to the PREI joint ventures, which are reflected in tenant recoveries and other income in the consolidated statements of income.

Derivatives_and_Other_Financia1

Derivatives and Other Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Summary of Derivative Instruments	'
											Fair-Value(1)
		Notional Amount									March 31,			December 31,
						Strike Rate			Effective Date	Expiration Date	2014			2013
	Interest rate swaps	$	200,000			1.163	%		March 30, 2012	March 30, 2017	$	(1,814	)	$	(1,876	)
	Interest rate swaps	200,000				0.701	%		October 1, 2013	October 1, 2016	(341		)	(288		)
	Interest rate swaps(2)	83,235				0.731	%		August 2, 2012	March 30, 2017	1,288			1,545
	Interest rate swaps(2)	83,235				0.7425	%		August 2, 2012	March 30, 2017	1,261			1,519
	Total interest rate swaps	$	566,470								394			900
	Other derivatives										578			416
	Total										$	972		$	1,316
	-1	Fair-value of derivative instruments does not include any related accrued interest payable, which is included in accrued expenses on the accompanying consolidated balance sheets. Derivative valuations are classified in Level 2 of the fair-value hierarchy. Assets are included in other assets and liabilities are included in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets.
	-2	Translations to U.S. dollars are based on exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively.
Summary of Derivative Instruments, Effect on OCI	'
	The following is a summary of the amount of loss recognized in other comprehensive income related to the derivative instruments (in thousands):
			Three Months Ended
			March 31,
			2014				2013
	Amount of loss recognized in other comprehensive income (effective portion):
	Cash flow hedges
	Interest rate swaps		$	(1,449	)		$	(697	)
	Amount of loss reclassified from accumulated other comprehensive loss to earnings(effective portion):
	Cash flow hedges
	Interest rate swaps (1)		$	859			$	560
	Forward starting swaps (2)		1,691				1,718
	Total interest rate swaps		$	2,550			$	2,278
	-1	Amount represents payments made to swap counterparties for the effective portion of interest rate swaps that were recognized as an increase to interest expense for the periods presented (the amount was recorded as an increase and corresponding decrease to accumulated other comprehensive loss in the same accounting period).
	-2	Amount represents reclassifications of deferred interest costs from accumulated other comprehensive loss to interest expense related to the Company’s previously settled forward starting swaps.

FairValue_of_Financial_Instrum1

Fair-Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair-Value and Carrying Value of the Company's Financial Instruments	'
	At March 31, 2014 and December 31, 2013, the aggregate fair-value and the carrying value of the Company’s financial instruments were as follows (in thousands):
		March 31, 2014						December 31, 2013
		Fair-Value (1)			Carrying Value			Fair-Value (1)			Carrying Value
	Mortgage notes payable, net	$	717,511		$	706,013		$	730,394		$	709,324
	Exchangeable Senior Notes	216,000			180,000			202,626			180,000
	Notes due 2016, net	419,792			398,912			417,040			398,787
	Notes due 2020, net	280,473			248,268			275,600			248,210
	Notes due 2022, net	247,903			248,132			240,400			248,086
	Term Loan due 2017 - U.S. dollar	244,664			243,596			244,751			243,596
	Term Loan due 2017 - GBP (2)	167,197			166,470			165,969			165,190
	Term Loan due 2018	350,000			350,000			350,000			350,000
	Unsecured line of credit	226,000			226,000			128,000			128,000
	Derivative instruments (3)	(972		)	(972		)	(1,316		)	(1,316		)
	Available-for-sale securities	33,279			33,279			19,566			19,566
	-1	Fair-values of debt and derivative instruments are classified in Level 2 of the fair-value hierarchy. Fair-value of available-for-sale securities are classified in Level 1 of the fair-value hierarchy.
	-2	The principal balance represents the U.S. dollar amount based on the exchange rate of $1.66 to £1.00 and $1.65 to £1.00 at March 31, 2014 and December 31, 2013, respectively.
	-3	The Company’s derivative instruments are reflected in other assets and in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets based on their respective balances (see Note 9).

Organization_of_the_Parent_Com1

Organization of the Parent Company and Description of Business (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Apr. 04, 2014	Apr. 04, 2014	Apr. 04, 2014	Apr. 04, 2014	Apr. 04, 2014	Apr. 04, 2014
			Parent Company	Parent Company	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	OneHundredCollegeStreet [Member]	ThreeHundredGeorgeStreet [Member]	Scenario, Forecast [Member]
					Three Hundred George Street and One College Street [Member]	ThreeHundredGeorgeStreet [Member]	OneHundredCollegeStreet [Member]	Subsequent Event [Member]	Subsequent Event [Member]	OneHundredCollegeStreet [Member]
					sqft	sqft	sqft			Subsequent Event [Member]
Organization, Consolidation and Presentation of Financial Statements	'	'	'	'	'	'	'	'	'	'
Equity Method Investment, Ownership Percentage	100.00%	100.00%	97.30%	97.30%	'	'	'	'	'	'
Remaining Ownership Interest Held by Limited Partners	2.70%	'	'	'	'	'	'	25.00%	7.00%	3.00%
Number of Real Estate Properties	'	'	'	'	2	'	'	'	'	'
Area of Real Estate Property	'	'	'	'	'	519,000	508,000	'	'	'
Real Estate Investment Property, Net	$5,235,036,000	$5,217,902,000	'	'	$308,000,000	'	'	'	'	'
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	'	'	'	'	206,000,000	'	'	'	'	'
Business Combination Construction Costs	'	'	'	'	$102,000,000	'	'	'	'	'

Basis_of_Presentation_and_Summ3

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	VIEs
	Extensions
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Real Estate Investment Property, Net	$5,235,036,000	'	$5,217,902,000
Number of Variable Interest Entities that the Company is the Primary Beneficiary	5	'	'
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	-1,300,000	'	'
Receivable with Imputed Interest, Due Date	30-Sep-14	'	'
Number of extension options	2	'	'
Extension options	'1 year	'	'
Debt Instrument, Basis Spread on Variable Rate	550.00%	'	'
Debt Instrument, Interest Rate, Stated Percentage	6.50%	'	'
Investment In Construction Loan	191,300,000	'	151,800,000
Lease Termination Revenue	5,500,000	24,000,000	'
Historic Tax Credit Recapture Period	'1 year	'	'
Deferred Costs and Other Assets	4,500,000	'	'
Tax credits, net of costs and estimated put paments	15,500,000	'	'
Tax Credits Delivered	-12,800,000	'	'
Foreign	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Revenue from properties outside the United States, net	4,800,000	4,500,000	'
Percentage of Company's total revenue	2.80%	'	'
Real Estate Investment Property, Net	190,700,000	'	190,200,000
Boston Development Project	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
BioMed Realty Trust Interest in Construction Loan	255,000,000	'	'
Construction Loan	355,000,000	'	'
Square Footage of Real Estate Property	1,100,000	'	'
Percent Leased	95.00%	'	'
Science Center at Oyster Point	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Lease Termination Revenue	'	'	$46,500,000
Historic and New Market Tax Credits [Member]	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Syndicated Historic Tax Credits and New Market Tax Credits	9	'	'
Historic tax credit [Member]	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Percentage Of Qualified Investments	39.00%	'	'
Percentage Of Tax Credit Recapture	20.00%	'	'
New Market Tax Credits [Member]	'	'	'
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]	'	'	'
Percentage Of Tax Credit Recapture	100.00%	'	'

Basis_of_Presentation_and_Summ4

Basis of Presentation and Summary of Significant Accounting Policies (Selected Financial Data of the VIEs) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounting Policies [Abstract]	'	'
Investment in Real Estate, Net	$339,284	$336,832
Total Assets	378,961	375,443
Total Debt	142,564	143,067
Total Liabilities	$156,186	$154,953

Basis_of_Presentation_and_Summ5

Basis of Presentation and Summary of Significant Accounting Policies (Investments in Real Estate, Net) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounting Policies [Abstract]	'	'
Land	$717,328	$713,955
Land Under Development	116,220	119,325
Buildings and Improvements	4,907,630	4,854,175
Construction in Progress	329,803	316,025
Real Estate Investment Property, at Cost	6,070,981	6,003,480
Accumulated Depreciation	-835,945	-785,578
Real Estate Investment Property, Net	$5,235,036	$5,217,902

Basis_of_Presentation_and_Summ6

Basis of Presentation and Summary of Significant Accounting Policies (Deferred Leasing Costs, Net) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Leasing Costs	'	'
Finite-Lived Intangible Assets, Gross	$486,018	$482,696
Finite-Lived Intangible Assets, Accumulated Amortization	-296,491	-284,629
Finite-Lived Intangible Assets, Net	189,527	198,067
Leases, Acquired-in-Place	'	'
Deferred Leasing Costs	'	'
Finite-Lived Intangible Assets, Gross	365,944	365,753
Finite-Lived Intangible Assets, Accumulated Amortization	-243,437	-233,935
Finite-Lived Intangible Assets, Net	122,507	131,818
Acquired Management Agreements	'	'
Deferred Leasing Costs	'	'
Finite-Lived Intangible Assets, Gross	25,801	25,801
Finite-Lived Intangible Assets, Accumulated Amortization	-20,502	-20,053
Finite-Lived Intangible Assets, Net	5,299	5,748
Deferred Leasing and Other Direct Costs	'	'
Deferred Leasing Costs	'	'
Finite-Lived Intangible Assets, Gross	94,273	91,142
Finite-Lived Intangible Assets, Accumulated Amortization	-32,552	-30,641
Finite-Lived Intangible Assets, Net	$61,721	$60,501

Basis_of_Presentation_and_Summ7

Basis of Presentation and Summary of Significant Accounting Policies (Investments) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Accounting Policies [Abstract]	'		'
Available-for-sale securities, historical cost	$7,191		$8,543
Unrealized gain, net	26,088		11,023
Available-for-sale securities, fair-value	33,279	[1]	19,566	[1]
Privately-held securities, cost basis	17,107		18,485
Total equity securities	$50,386		$38,051
[1]	Determination of fair-value is classified as Level 1 in the fair-value hierarchy based on the use of quoted prices in active markets.

Basis_of_Presentation_and_Summ8

Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Summary of Significant Accounting Policies (Selected Financial Data and VIEs, Wexford) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Variable Interest Entity [Line Items]	'	'
Variable Interest Entity Carrying Amount Of Collateralized Investment In Real Estate Net	$339,284	$336,832
Variable Interest Entity, Consolidated, Carrying Amount, Assets	378,961	375,443
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	156,186	154,953
Wexford Merger [Member]	'	'
Variable Interest Entity [Line Items]	'	'
Variable Interest Entity Carrying Amount Of Collateralized Investment In Real Estate Net	181,458	177,901
Variable Interest Entity, Consolidated, Carrying Amount, Assets	193,789	198,968
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$63,877	$60,197

Equity_of_the_Parent_Company_N

Equity of the Parent Company (Narrative) (Details) (USD $)

3 Months Ended

3 Months Ended

Mar. 31, 2014

Sep. 30, 2013

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2012

Mar. 31, 2014

Dec. 31, 2013

Parent Company

Parent Company

Parent Company

Parent Company

Parent Company

Parent Company

Parent Company

BIOMED REALTY, L.P.

BIOMED REALTY, L.P.

Performance Shares

Performance Shares

Limited Partner

Limited Partner

Common Stock

Common Stock

Operating Partnership Units and LTIP Units

Restricted Stock Issued to Employees

Parent Company

Parent Company

BIOMED REALTY, L.P.

BIOMED REALTY, L.P.

Common Stock

Common Stock

Equity of the Parent Company

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted Stock Awards Issued

'

'

'

'

'

'

557,237

'

'

'

'

'

'

Shares surrendered to the Company and retired in lieu of cash payments for taxes due on the vesting of restricted stock

-190,062

'

'

'

'

'

'

'

'

-7,243

'

'

'

Shares forfeited during the period

2,693

'

'

'

'

'

'

'

'

'

'

'

'

Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures

'

'

'

377,463

'

'

'

'

'

'

'

'

'

Performance units forfeited during the period

'

'

'

'

'

'

'

'

'

116,072

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value

$3,800,000

'

'

'

'

'

'

'

'

'

'

'

'

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition

'2 years 9 months

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value

3,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Performance units

'

'

'

'

'

'

'

'

'

494,410

136,296

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period

'

'

'

'

'

'

'

'

'

20,224

'

'

'

Stock Issued During Period, Value, New Issues

-49,000

'

'

'

'

'

'

-49,000

'

'

'

'

'

Proceeds from Issuance of Common Stock

'

'

299,402,000

'

'

'

'

'

'

'

'

'

'

Common Stock, Shares Outstanding

'

'

'

192,502,965

192,115,002

'

'

'

'

'

'

'

'

Partnership Units, Shares Outstanding

'

'

'

'

'

5,083,400

'

'

'

'

'

5,405,474

5,415,974

LTIP Units, Shares Outstanding

'

'

'

'

'

322,074

'

'

'

'

'

'

'

Payments of Ordinary Dividends, Preferred Stock and Preference Stock

'

'

6,044,000

'

'

'

'

'

6,044,000

'

'

'

'

Cost on redemption of preferred stock / units

'

'

-6,531,000

'

'

'

'

'

-6,531,000

'

'

'

'

Noncontrolling Interest Redemption Value

$109,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Average Closing Price Per Common Share

$20.16

'

'

'

'

'

'

'

'

'

'

'

'

Noncontrolling Interest Redemption Value Calculation Days

'10 days

'10 days

'

'

'

'

'

'

'

'

'

'

'

Equity_of_the_Parent_Company_D

Equity of the Parent Company (Dividends and Distributions) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
	Common stock and OP units	Parent Company
Equity of the Parent Company	'	'
Declaration Date	17-Mar-14	'
Amount Per Common Share/Unit	$0.25	'
Dividend and Distribution Payable Date	15-Apr-14	'
Dividend and Distribution Amount	$49,479	'
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	'	$6,044

Equity_of_the_Parent_Company_E

Equity of the Parent Company Equity of the Parent Company (Changes in Accumulated Other Comprehensive Loss by Component) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Other Comprehensive Income (Loss), Net of Tax	$10,100		'	'
Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Accumulated other comprehensive loss, net	-19,973		'	-32,923
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	23,423		'	'
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,974,883		'	2,987,025
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	24,634		'	'
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	1,691		'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-6,772	[1]	'	'
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	24,634		-168	'
Other Comprehensive Income (Loss), Net of Tax	16,651		-769	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	5,635		132	'
Accumulated Translation Adjustment [Member] | Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Accumulated other comprehensive loss, net	4,137		'	3,905
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	238		'	'
Other Comprehensive Income (Loss), Net of Tax	238		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	-6		'	'
Accumulated Other Comprehensive Income (Loss) | Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	-19,973		'	-32,923
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	19,430		'	'
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	1,646		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	-3,701		'	'
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Accumulated other comprehensive loss, net	20,584		'	8,938
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	24,634		'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-9,322	[1]	'	'
Other Comprehensive Income (Loss), Net of Tax	15,312		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	-3,666		'	'
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Accumulated other comprehensive loss, net	-44,694		'	-45,766
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,550	[1]	'	'
Other Comprehensive Income (Loss), Net of Tax	1,101		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	-29		'	'
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Interest Rate Swaps | Parent Company	'		'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'		'	'
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	($1,449)		'	'
[1]	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.

Equity_of_the_Parent_Company_V

Equity of the Parent Company (Vested Ownership Interests) (Details)	Mar. 31, 2014	Dec. 31, 2013
Equity of the Parent Company	'	'
Operating Partnership Units and LTIP Units	196,279,821	195,959,961
Equity Method Investment, Ownership Percentage	100.00%	100.00%
Parent Company	'	'
Equity of the Parent Company	'	'
Operating Partnership Units and LTIP Units	191,006,788	190,676,428
Equity Method Investment, Ownership Percentage	97.30%	97.30%
Operating Partnership and LTIP Units Held By Employees and Related Parties	'	'
Equity of the Parent Company	'	'
Operating Partnership Units and LTIP Units	2,645,888	2,656,388
Equity Method Investment, Ownership Percentage	1.40%	1.40%
Operating Partnership and LTIP Units Held By Third Parties	'	'
Equity of the Parent Company	'	'
Operating Partnership Units and LTIP Units	2,627,145	2,627,145
Equity Method Investment, Ownership Percentage	1.30%	1.30%

Capital_of_the_Operating_Partn2

Capital of the Operating Partnership (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Sep. 30, 2013	Mar. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified			BIOMED REALTY, L.P.	Parent Company	Parent Company	Parent Company	Parent Company
Capital of the Operating Partnership [Line Items]	'	'	'	'	'	'	'
Partners' Capital Account, Units	'	'	197,586,365	'	'	'	'
LTIP Units, Shares Outstanding	'	'	322,074	'	'	'	'
Equity Method Investment, Ownership Percentage	100.00%	100.00%	'	'	'	97.30%	97.30%
Noncontrolling Interest Redemption Value	'	'	'	$109	'	'	'
Average Closing Price Per Common Share	'	'	'	$20.16	'	'	'
Noncontrolling Interest Redemption Value Calculation Days	'	'	'	'10 days	'10 days	'	'

Capital_of_the_Operating_Partn3

Capital of the Operating Partnership Capital of the Operating Partnership (Changes in Accumulated Other Comprehensive Loss by Component) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Capital of the Operating Partnership [Line Items]	'		'	'
Other Comprehensive Income (Loss), Net of Tax	$10,100		'	'
BIOMED REALTY, L.P.	'		'	'
Capital of the Operating Partnership [Line Items]	'		'	'
Accumulated other comprehensive loss, net	-17,356		'	-30,663
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	23,423		'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-6,772	[1]	'	'
Other Comprehensive Income (Loss), Net of Tax	16,651		-769	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	4,757		-8	'
Accumulated Translation Adjustment [Member] | BIOMED REALTY, L.P.	'		'	'
Capital of the Operating Partnership [Line Items]	'		'	'
Accumulated other comprehensive loss, net	4,244		'	4,006
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	238		'	'
Other Comprehensive Income (Loss), Net of Tax	238		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	0		'	'
Accumulated Net Unrealized Investment Gain (Loss) [Member] | BIOMED REALTY, L.P.	'		'	'
Capital of the Operating Partnership [Line Items]	'		'	'
Accumulated other comprehensive loss, net	21,154		'	9,186
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	24,634		'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-9,322	[1]	'	'
Other Comprehensive Income (Loss), Net of Tax	15,312		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	-3,344		'	'
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | BIOMED REALTY, L.P.	'		'	'
Capital of the Operating Partnership [Line Items]	'		'	'
Accumulated other comprehensive loss, net	-42,754		'	-43,855
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-1,449		'	'
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,550	[1]	'	'
Other Comprehensive Income (Loss), Net of Tax	1,101		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	0		'	'
Accumulated Other Comprehensive Income (Loss) | BIOMED REALTY, L.P.	'		'	'
Capital of the Operating Partnership [Line Items]	'		'	'
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	($3,344)		'	'
[1]	Amounts reclassified from unrealized gain on available-for-sale securities are included in other income, net in the consolidated statements of income. Amounts reclassified from loss on derivative instruments are included in interest expense, net in the consolidated statements of income. See Note 9 for further information on derivative instruments.

Debt_Debt_Narrative_Details

Debt Debt (Narrative) (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 27, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Jun. 30, 2014

Apr. 24, 2014

Apr. 04, 2014

Apr. 04, 2014

Interest Rate Swaps

Interest Rate Swaps

Exchangeable Senior Notes

Mortgage Notes Payable

Mortgage Notes Payable

Unsecured Line of Credit

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan Due 2018 [Member]

Unsecured Term Loan Due 2018 [Member]

Unsecured Term Loans

Unsecured Term Loans

Unsecured Senior Notes Due Twenty Twenty [Member]

Unsecured Senior Notes Due Twenty Twenty-Two [Member]

Unsecured Senior Notes Due Twenty Sixteen [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Interest Rate Swaps - $200M (2)

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Debt [Member]

Unsecured Debt [Member]

Unsecured Debt [Member]

Unsecured Senior Notes Due Twenty Nineteen [Member]

Unsecured Senior Notes Due Twenty Nineteen [Member]

ThreeHundredGeorgeStreet [Member]

OneHundredCollegeStreet [Member]

Unsecured Debt [Member]

Unsecured Debt [Member]

Mortgage Notes Payable

Mortgage Notes Payable

Debt Instruments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increment of Dividends per Common Share Increase Exchange Rate

'

'

'

'

$0.14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign Currency Exchange Rate, Translation

'

'

'

'

'

'

'

'

'

'

1.66

1.65

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Interest Rate, Stated Percentage

6.50%

'

'

'

3.75%

'

'

1.45%

[1]

'

'

'

'

2.13%

[2]

'

1.65%

'

1.80%

[2]

'

6.13%

4.25%

3.85%

'

2.63%

'

'

Percentage Of Long Term Debt Principal Paid By Underwriters

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

99.41%

'

'

Effective Interest Rate

'

'

'

'

3.75%

'

'

1.45%

[1]

'

'

'

'

2.39%

[2]

'

1.97%

'

2.63%

[2]

'

6.27%

4.36%

3.99%

'

2.75%

'

'

Debt Instrument Payable Dates

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

' May 1 and November 1

'

'

'

Debt Instrument, Date of First Required Payment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-Nov-14

'

'

'

Debt Instrument, Maturity Date

'

'

'

'

15-Jan-30

'

'

24-Mar-18

[1]

'

'

'

'

30-Mar-17

[2]

'

24-Mar-18

'

30-Mar-17

[2]

'

15-Apr-20

15-Jul-22

15-Apr-16

1-May-19

'

'

'

Debt Instrument, Basis Spread on Variable Rate

550.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative, Inception Date

'

'

'

1-Oct-13

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative, Notional Amount

'

'

$566,470,000

$200,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal Balance

2,761,337,000

'

'

'

'

695,271,000

698,048,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

46,300,000

21,700,000

Unsecured Term Loans

'

'

'

'

'

'

'

'

760,066,000

758,786,000

'

'

166,470,000

[2]

165,190,000

[2]

350,000,000

350,000,000

243,596,000

[2]

243,596,000

[2]

'

'

'

'

'

'

'

Debt Instrument, Convertible, Conversion Ratio

'

'

'

'

58.4745

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Conversion, Original Debt, Amount

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Conversion Price

'

$17.10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends Payable Date of Ex-Dividend

'

'

'

'

27-Mar-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Issuance Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

23-Apr-14

'

'

'

Debt Instrument, Face Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$400,000,000

'

'

[1]

At MarchB 31, 2014, the Operating Partnership had additional borrowing capacity under the unsecured line of credit of up to approximately $674.0 million.

[2]

In August 2012, the Operating Partnership converted approximately $156.4 million of outstanding borrowings into British pounds sterling (bGBPb) equal to £100.0 million, which was designated as a net investment hedge to mitigate the risk of fluctuations in foreign currency exchange rates. The principal balance represents the U.S. dollar amount based on the exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at MarchB 31, 2014 and DecemberB 31, 2013, respectively. The effective interest rate includes the impact of interest rate swap agreements (see Note 9 for further discussion of interest rate swap agreements).

Debt_Summary_of_the_Operating_

Debt (Summary of the Operating Partnership's Outstanding Consolidated Debt) (Details)

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

USD ($)

USD ($)

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Mortgage Notes Payable

Exchangeable Senior Notes

Exchangeable Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Senior Notes

Unsecured Term Loans

Unsecured Term Loans

Unsecured Line of Credit

Unsecured Line of Credit

Unsecured Line of Credit and Term Loan

Unsecured Term Loan USD Portion [Member]

Unsecured Term Loan USD Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan GBP Portion [Member]

Unsecured Term Loan Due 2018 [Member]

Unsecured Term Loan Due 2018 [Member]

USD ($)

USD ($)

9900 Belward Campus Drive

9900 Belward Campus Drive

9901 Belward Campus Drive

9901 Belward Campus Drive

Center for Life Science Boston

Center for Life Science Boston

4320 Forest Park Avenue

4320 Forest Park Avenue

Hershey Center for Applied Research

Hershey Center for Applied Research

500 Kendall Street (Kendall D)

500 Kendall Street (Kendall D)

Shady Grove Road

Shady Grove Road

University of Maryland BioPark I

University of Maryland BioPark I

University of Maryland BioPark II

University of Maryland BioPark II

University of Maryland BioPark Garage

University of Maryland BioPark Garage

University of Miami Life Science & Technology Park

University of Miami Life Science & Technology Park

USD ($)

USD ($)

USD ($)

USD ($)

Unsecured Senior Notes Due Twenty Sixteen [Member]

Unsecured Senior Notes Due Twenty Sixteen [Member]

Unsecured Senior Notes Due Twenty Twenty [Member]

Unsecured Senior Notes Due Twenty Twenty [Member]

Unsecured Senior Notes Due Twenty Twenty-Two [Member]

Unsecured Senior Notes Due Twenty Twenty-Two [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

Unsecured Term Loans

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD

GBP [Member]

USD ($)

USD ($)

USD ($)

GBP (£)

Debt Instruments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stated Interest Rate

6.50%

'

'

'

5.64%

'

5.64%

'

7.75%

[1]

'

4.00%

'

6.15%

'

6.38%

'

5.97%

'

5.93%

[1]

'

5.20%

[1]

'

5.20%

[1]

'

4.00%

[1]

'

3.75%

'

'

'

3.85%

'

6.13%

'

4.25%

'

'

'

1.45%

[2]

'

'

1.80%

[3]

'

'

'

2.13%

[3]

'

'

'

1.65%

'

Effective Interest Rate

'

'

'

'

3.99%

'

3.99%

'

7.75%

[1]

'

2.70%

'

4.71%

'

5.45%

'

5.97%

'

4.69%

[1]

'

4.33%

[1]

'

4.33%

[1]

'

2.89%

[1]

'

3.75%

'

'

'

3.99%

'

6.27%

'

4.36%

'

'

'

1.45%

[2]

'

'

2.63%

[3]

'

'

'

2.39%

[3]

'

'

'

1.97%

'

Principal Balance

$2,761,337,000

'

$695,271,000

$698,048,000

$10,593,000

$10,631,000

$13,045,000

$13,091,000

$333,398,000

[1]

$334,447,000

[1]

$21,000,000

$21,000,000

$13,328,000

$13,449,000

$57,346,000

$57,927,000

$142,564,000

$143,067,000

$16,587,000

[1]

$16,752,000

[1]

$62,691,000

[1]

$62,946,000

[1]

$4,719,000

[1]

$4,738,000

[1]

$20,000,000

[1]

$20,000,000

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized Premiums

'

'

10,742,000

11,276,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Mortgage Notes Payable, net

'

'

706,013,000

709,324,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exchangeable Senior Notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

180,000,000

180,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unsecured Senior Notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

900,000,000

900,000,000

400,000,000

400,000,000

250,000,000

250,000,000

250,000,000

250,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized Discounts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4,688,000

-4,917,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unsecured Senior Notes, net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

895,312,000

895,083,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unsecured Term Loans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

760,066,000

758,786,000

'

'

'

243,596,000

[3]

243,596,000

[3]

'

'

166,470,000

[3]

165,190,000

[3]

156,400,000

[3]

100,000,000

[3]

350,000,000

350,000,000

Unsecured Line of Credit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

226,000,000

[2]

128,000,000

[2]

'

'

'

'

'

'

'

'

'

'

'

Total Consolidated Debt

2,767,391,000

2,671,193,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity Date

'

'

'

'

1-Jul-17

'

1-Jul-17

'

30-Jun-14

[1]

'

30-Jun-15

'

5-May-27

'

1-Dec-18

'

1-Sep-16

'

15-May-25

[1]

'

5-Sep-21

[1]

'

1-Sep-21

[1]

'

1-Feb-16

[1]

'

15-Jan-30

'

'

'

15-Apr-16

'

15-Apr-20

'

15-Jul-22

'

'

'

24-Mar-18

[2]

'

'

30-Mar-17

[3]

'

'

'

30-Mar-17

[3]

'

'

'

24-Mar-18

'

Foreign Currency Exchange Rate, Translation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.66

1.65

'

'

'

'

'

'

LOC Remaining Borrowing Capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$674,000,000

'

'

'

'

'

'

'

'

'

'

[1]

On April 1, 2014, the Operating Partnership repaid in full the mortgage loan secured by the Companybs Center for Life Science | Boston property prior to its scheduled maturity date.

[2]

At MarchB 31, 2014, the Operating Partnership had additional borrowing capacity under the unsecured line of credit of up to approximately $674.0 million.

[3]

In August 2012, the Operating Partnership converted approximately $156.4 million of outstanding borrowings into British pounds sterling (bGBPb) equal to £100.0 million, which was designated as a net investment hedge to mitigate the risk of fluctuations in foreign currency exchange rates. The principal balance represents the U.S. dollar amount based on the exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at MarchB 31, 2014 and DecemberB 31, 2013, respectively. The effective interest rate includes the impact of interest rate swap agreements (see Note 9 for further discussion of interest rate swap agreements).

Debt_Principal_Payments_Due_fo

Debt (Principal Payments Due for Operating Partnership's Consolidated Indebtedness) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Year 1	$338,639		'
Year 2	30,006		'
Year 3	566,516		'
Year 4	440,360		'
Year 5	621,663		'
Thereafter	764,153	[1]	'
Principal Balance	2,761,337		'
Exchangeable Senior Notes	'		'
Exchangeable Senior Notes	$180,000		$180,000
Maturity Date	15-Jan-30		'
[1]	Includes $180.0 million in principal payments of the Exchangeable Senior Notes based on a contractual maturity date of JanuaryB 15, 2030.

Earnings_Per_Share_of_the_Pare2

Earnings Per Share of the Parent Company (Narrative) (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
BIOMED REALTY, L.P.	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share	'	'
Exchangeable Senior Notes Due 2030	10,525,410	10,259,496
Parent Company	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share	'	'
Exchangeable Senior Notes Due 2030	10,525,410	10,259,496

Earnings_Per_Share_of_the_Pare3

Earnings Per Share of the Parent Company (Schedule of Earnings Per Share, Basic and Diluted) (Details) (Parent Company, USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Parent Company	'	'
Schedule of Earnings Per Share Basic and Diluted	'	'
Income from continuing operations and noncontrolling interests	$20,767	$17,458
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest	-1,934	-146
Preferred Stock Dividends and Other Adjustments	'	-2,393
Cost On Redemption Of Preferred Stock	'	-6,531
Participating Securities, Distributed and Undistributed Earnings	-378	-345
Net Income (Loss) Available to Common Stockholders, Basic	18,455	8,043
Income (loss) from continuing operations attributable to noncontrollinginterests diluted	521	159
Net Income (Loss) Available to Common Stockholders, Diluted	$18,976	$8,202
Weighted Average Number of Shares Outstanding, Basic	190,905,867	159,692,470
Amount of Dilutive Securities Performance Units	229,295	97,788
Amount Of Dilutive Securities Operating Partnership And Ltip Units	5,410,374	2,923,419
Basic and Diluted	196,545,536	162,713,677
Earnings Per Share, Basic and Diluted	$0.10	$0.05

Earnings_Per_Unit_of_the_Opera2

Earnings Per Unit of the Operating Partnership Earnings Per Unit of the Operating Partnership (Narrative) (Details) (BIOMED REALTY, L.P.)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
BIOMED REALTY, L.P.	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share	'	'
Exchangeable Senior Notes Due 2030	10,525,410	10,259,496

Earnings_Per_Unit_of_the_Opera3

Earnings Per Unit of the Operating Partnership (Computations of Basic and Diluted Earnings Per Unit) (Details) (BIOMED REALTY, L.P., USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
BIOMED REALTY, L.P.	'	'
Earnings Per Unit of the Operating Partnership	'	'
Income from continuing operations and noncontrolling interests	$20,767	$17,458
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest	-1,413	8
Preferred Stock Dividends and Other Adjustments	'	-2,393
Cost On Redemption Of Preferred Stock	'	-6,531
Participating Securities, Distributed and Undistributed Earnings	-378	-345
Net Income Loss Attributable To Unit Holders Basic and Diluted	$18,976	$8,197
Weighted Average Number of Shares Outstanding, Basic	196,316,241	162,612,998
Amount of Dilutive Securities Performance Units	229,295	97,788
Basic and Diluted	196,545,536	162,710,786
Net Income per Unit Attributable to Unitholders, Basic and Diluted	$0.10	$0.05

Investment_in_Unconsolidated_P2

Investment in Unconsolidated Partnerships (Narrative) (Details)	Mar. 31, 2014
	PREI_LLCs
Equity Method Investments and Joint Ventures [Abstract]	'
Number of Investments in Limited Liability Companies	2

Investment_in_Unconsolidated_P3

Investment in Unconsolidated Partnerships (Summary of Unconsolidated Partnerships) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014		Mar. 31, 2014	Mar. 31, 2014		Mar. 31, 2014
In Millions, unless otherwise specified			PREI I LLC		PREI II LLC	McKellar Court		BioPark Fremont
			properties
Investment In Unconsolidated Partnerships	'	'	'		'	'		'
Equity Method Investment, Ownership Percentage	100.00%	100.00%	20.00%	[1]	20.00%	22.00%	[2]	50.00%
Company's Economic Interest	'	'	20.00%	[1]	20.00%	22.00%	[2]	50.00%
Date Acquired	'	'	4-Apr-07	[1]	4-Apr-07	30-Sep-04	[2]	31-May-13
Number Of Properties In Portfolio Of Prei I Llc	'	'	2		'	'		'
Line of Credit Facility, Amount Outstanding	'	'	$139		'	'		'
Line Of Credit Facility Weighted Average Interest Rate	'	'	3.16%		'	'		'
Line of Credit Facility, Expiration Date	'	'	13-Aug-14		'	'		'
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	'	'	'		'	$12		'
Percent Of Extraordinary Cash Flow Entitled From Variable Interest Entity	'	'	'		'	75.00%		'
Percent Of Operating Cash Flows Entitled From Variable Interest Entity	'	'	'		'	22.00%		'
[1]	PREI I LLC owns two properties in Cambridge, Massachusetts. At MarchB 31, 2014, there were $139.0 million in outstanding borrowings on a secured loan facility held by a wholly-owned subsidiary of PREI I LLC, with a contractual interest rate of 3.16% (including the applicable credit spread) and a maturity date of AugustB 13, 2014. At maturity, PREI I LLC may refinance the secured loan facility, depending on market conditions and the availability of credit, or it may repay the principal balance through capital contributions of its members.
[2]	The Companybs investment in the McKellar Court partnership (maximum exposure to losses) was approximately $12.0 million at MarchB 31, 2014. The Companybs economic interest in the McKellar Court partnership entitles it to 75% of the extraordinary cash flows after repayment of the partnersb capital contributions and 22% of the operating cash flows.

Investment_in_Unconsolidated_P4

Investment in Unconsolidated Partnerships (Summary of Selected Balance Sheet Information) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Equity Method Investments and Joint Ventures [Abstract]	'	'
Investments in real estate, net	$271,132	$262,753
Cash and cash equivalents (including restricted cash)	5,612	3,855
Other assets	3,758	5,301
Total assets	280,502	271,909
Mortgage notes payable and secured loan	151,992	151,968
Other liabilities	23,541	12,102
Members' equity	104,969	107,839
Total liabilities and equity	280,502	271,909
Company's net investment in unconsolidated partnerships	$31,461	$32,137

Investment_in_Unconsolidated_P5

Investment in Unconsolidated Partnerships (Summary of Selected Income Statement Information) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'		'
Total revenues	$4,059		$2,830
Total expenses	-6,130		-5,448
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	-2,071		-2,618
Company's equity in net loss of unconsolidated partnerships	-138		-319
Fees earned by the Company	$283	[1]	$22	[1]
[1]	The Company acts as the operating member or partner, as applicable, and day-to-day manager for the partnerships. The Company is entitled to receive fees for providing construction and development services (as applicable) and management services to the PREI joint ventures, which are reflected in tenant recoveries and other income in the consolidated statements of income.

Derivatives_and_Other_Financia2

Derivatives and Other Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Derivative	'		'
Other Comprehensive Income (Loss), Net of Tax	$10,100,000		'
Period Swaps Effectively Fix Interest Rate	'3 years		'
Derivative, Deferred Interest Costs Amortization Period	'5 years		'
Other Income	2,550,000		2,278,000
Unrealized gain on derivative instruments, net	162,000		'
Interest Rate Swaps	'		'
Derivative	'		'
Derivative, Notional Amount	566,470,000		'
Other Income	859,000	[1]	560,000	[1]
Forward Starting Swaps	'		'
Derivative	'		'
Derivative, Deferred Interest Costs	33,700,000		'
Derivative, Lower Remaining Maturity Range	'10 years		'
Other Income	1,691,000	[2]	1,718,000	[2]
Interest Rate Swaps - $200M [Member] | Interest Rate Swaps	'		'
Derivative	'		'
Derivative, Maturity Date	30-Mar-17		'
Derivative, Inception Date	30-Mar-12		'
Derivative, Notional Amount	200,000,000		'
Interest Rate Swaps - $200M (2) | Interest Rate Swaps	'		'
Derivative	'		'
Derivative, Maturity Date	1-Oct-16		'
Derivative, Inception Date	1-Oct-13		'
Derivative, Notional Amount	$200,000,000		'
[1]	Amount represents payments made to swap counterparties for the effective portion of interest rate swaps that were recognized as an increase to interest expense for the periods presented (the amount was recorded as an increase and corresponding decrease to accumulated other comprehensive loss in the same accounting period).
[2]	Amount represents reclassifications of deferred interest costs from accumulated other comprehensive loss to interest expense related to the Companybs previously settled forward starting swaps.

Derivatives_and_Other_Financia3

Derivatives and Other Financial Instruments (Summary of Derivative Instruments) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Derivative	'		'
Derivative, Fair Value, Net	$972	[1]	$1,316	[1]
Unsecured Term Loan Due 2017 GBP Portion	'		'
Derivative	'		'
Foreign Currency Exchange Rate, Translation	1.66		1.65
Interest Rate Swaps	'		'
Derivative	'		'
Derivative, Notional Amount	566,470		'
Derivative, Fair Value, Net	394	[1]	900	[1]
Interest Rate Swaps | Interest Rate Swaps - $200M (1)	'		'
Derivative	'		'
Derivative, Notional Amount	200,000		'
Derivative, Fixed Interest Rate	1.16%		'
Derivative, Effective Date	30-Mar-12		'
Derivative, Maturity Date	30-Mar-17		'
Derivative, Fair Value, Net	-1,814	[1]	-1,876	[1]
Interest Rate Swaps | Interest Rate Swaps - $200M (2)	'		'
Derivative	'		'
Derivative, Notional Amount	200,000		'
Derivative, Fixed Interest Rate	0.70%		'
Derivative, Effective Date	1-Oct-13		'
Derivative, Maturity Date	1-Oct-16		'
Derivative, Fair Value, Net	-341	[1]	-288	[1]
Interest Rate Swaps | Interest Rate Swap - 50M GBP (1)	'		'
Derivative	'		'
Derivative, Notional Amount	83,235	[2]	'
Derivative, Fixed Interest Rate	0.73%	[2]	'
Derivative, Effective Date	2-Aug-12	[2]	'
Derivative, Maturity Date	30-Mar-17	[2]	'
Derivative, Fair Value, Net	1,288	[1],[2]	1,545	[1],[2]
Interest Rate Swaps | Interest Rate Swap - 50M GBP (2)	'		'
Derivative	'		'
Derivative, Notional Amount	83,235	[2]	'
Derivative, Fixed Interest Rate	0.74%	[2]	'
Derivative, Effective Date	2-Aug-12	[2]	'
Derivative, Maturity Date	30-Mar-17	[2]	'
Derivative, Fair Value, Net	1,261	[1],[2]	1,519	[1],[2]
Interest Rate Swaps | Other Derivatives [Domain]	'		'
Derivative	'		'
Derivative, Fair Value, Net	$578	[1]	$416	[1]
[1]	Fair-value of derivative instruments does not include any related accrued interest payable, which is included in accrued expenses on the accompanying consolidated balance sheets. Derivative valuations are classified in Level 2 of the fair-value hierarchy. Assets are included in other assets and liabilities are included in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets.
[2]	Translations to U.S. dollars are based on exchange rates of $1.66 to £1.00 and $1.65 to £1.00 at MarchB 31, 2014 and DecemberB 31, 2013, respectively.

Derivatives_and_Other_Financia4

Derivatives and Other Financial Instruments (Summary of Derivative Instruments, Effect on OCI) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Derivative	'		'
Other Income	$2,550		$2,278
Interest Rate Swaps	'		'
Derivative	'		'
Other Income	859	[1]	560	[1]
Forward Starting Swaps	'		'
Derivative	'		'
Other Income	1,691	[2]	1,718	[2]
Parent Company | Interest Rate Swaps	'		'
Derivative	'		'
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	($1,449)		($697)
[1]	Amount represents payments made to swap counterparties for the effective portion of interest rate swaps that were recognized as an increase to interest expense for the periods presented (the amount was recorded as an increase and corresponding decrease to accumulated other comprehensive loss in the same accounting period).
[2]	Amount represents reclassifications of deferred interest costs from accumulated other comprehensive loss to interest expense related to the Companybs previously settled forward starting swaps.

FairValue_of_Financial_Instrum2

Fair-Value of Financial Instruments (Fair-Value and Carrying Value of the Company's Financial Instruments) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Fair-Value of Financial Instruments	'		'
Available-for-sale securities	$33,279	[1]	$19,566	[1]
Unsecured Term Loan Due 2017 GBP Portion	'		'
Fair-Value of Financial Instruments	'		'
Foreign Currency Exchange Rate, Translation	1.66		1.65
Mortgage Notes Payable	'		'
Fair-Value of Financial Instruments	'		'
Mortgage notes payable, net	706,013		709,324
Exchangeable Senior Notes	'		'
Fair-Value of Financial Instruments	'		'
Exchangeable senior notes	180,000		180,000
Unsecured Senior Notes	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	895,312		895,083
Unsecured Line of Credit	'		'
Fair-Value of Financial Instruments	'		'
Unsecured line of credit	226,000	[2]	128,000	[2]
Fair-Value	'		'
Fair-Value of Financial Instruments	'		'
Available-for-sale securities	33,279	[3]	19,566	[3]
Fair-Value | Mortgage Notes Payable	'		'
Fair-Value of Financial Instruments	'		'
Mortgage notes payable, net	717,511	[3]	730,394	[3]
Fair-Value | Exchangeable Senior Notes	'		'
Fair-Value of Financial Instruments	'		'
Exchangeable senior notes	216,000	[3]	202,626	[3]
Fair-Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Sixteen [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	419,792	[3]	417,040	[3]
Fair-Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Twenty [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	280,473	[3]	275,600	[3]
Fair-Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Twenty-Two [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	247,903	[3]	240,400	[3]
Fair-Value | Unsecured Term Loans | Unsecured Term Loan USD Portion [Member] | USD	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	244,664	[3]	244,751	[3]
Fair-Value | Unsecured Term Loans | Unsecured Term Loan Due 2017 GBP Portion | GBP [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	167,197	[3],[4]	165,969	[3],[4]
Fair-Value | Unsecured Term Loans | Unsecured Term Loan Due 2018 [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	350,000	[3]	350,000	[3]
Fair-Value | Unsecured Line of Credit	'		'
Fair-Value of Financial Instruments	'		'
Unsecured line of credit	226,000	[3]	128,000	[3]
Carrying Value	'		'
Fair-Value of Financial Instruments	'		'
Derivative Instruments	-972	[3],[5]	-1,316	[3],[5]
Available-for-sale securities	33,279		19,566
Carrying Value | Mortgage Notes Payable	'		'
Fair-Value of Financial Instruments	'		'
Mortgage notes payable, net	706,013		709,324
Carrying Value | Exchangeable Senior Notes	'		'
Fair-Value of Financial Instruments	'		'
Exchangeable senior notes	180,000		180,000
Carrying Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Sixteen [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	398,912		398,787
Carrying Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Twenty [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	248,268		248,210
Carrying Value | Unsecured Senior Notes | Unsecured Senior Notes Due Twenty Twenty-Two [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior notes, net	248,132		248,086
Carrying Value | Unsecured Term Loans | Unsecured Term Loan USD Portion [Member] | USD	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	243,596		243,596
Carrying Value | Unsecured Term Loans | Unsecured Term Loan Due 2017 GBP Portion | GBP [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	166,470	[4]	165,190	[4]
Carrying Value | Unsecured Term Loans | Unsecured Term Loan Due 2018 [Member]	'		'
Fair-Value of Financial Instruments	'		'
Unsecured senior term loans	350,000		350,000
Carrying Value | Unsecured Line of Credit	'		'
Fair-Value of Financial Instruments	'		'
Unsecured line of credit	$226,000		$128,000
[1]	Determination of fair-value is classified as Level 1 in the fair-value hierarchy based on the use of quoted prices in active markets.
[2]	At MarchB 31, 2014, the Operating Partnership had additional borrowing capacity under the unsecured line of credit of up to approximately $674.0 million.
[3]	Fair-values of debt and derivative instruments are classified in Level 2 of the fair-value hierarchy. Fair-value of available-for-sale securities are classified in Level 1 of the fair-value hierarchy.
[4]	The principal balance represents the U.S. dollar amount based on the exchange rate of $1.66 to £1.00 and $1.65 to £1.00 at MarchB 31, 2014 and DecemberB 31, 2013, respectively.
[5]	The Companybs derivative instruments are reflected in other assets and in accounts payable, accrued expenses and other liabilities on the accompanying consolidated balance sheets based on their respective balances (see Note 9).