Condensed consolidating financial information (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Activities
Net income	$ 30,237	$ 32,775
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	46,995	43,405
Loss on early extinguishment of debt		623
Gain on sale of land parcel		(1,864)
Loss on sale of real estate	340
Amortization of loan fees and costs	2,386	2,643
Amortization of debt premiums/discounts	115	179
Amortization of acquired above and below market leases	(830)	(800)
Deferred rent	(6,198)	(8,796)
Stock compensation expense	3,349	3,293
Equity in income related to investments		26
Gain on sales of investments	(446)	(1,999)
Loss on sales of investments	386	1
Changes in operating assets and liabilities:
Restricted cash	1,506	862
Tenant receivables	(818)	(1,237)
Deferred leasing costs	(11,757)	(7,011)
Other assets	(7,302)	(2,411)
Accounts payable, accrued expenses, and tenant security deposits	(10,722)	(10,004)
Net cash provided by operating activities	47,241	49,685
Investing Activities
Proceeds from sale of properties	80,203
Additions to properties	(139,245)	(120,585)
Purchase of properties		(19,946)
Change in restricted cash related to construction projects	(17)	(1,400)
Distribution from unconsolidated real estate entity		22,250
Contributions to unconsolidated real estate entity	(2,074)	(3,914)
Additions to investments	(10,363)	(5,438)
Proceeds from investments	1,972	4,785
Net cash used in investing activities	(69,524)	(124,248)
Financing Activities
Principal borrowings from secured notes payable	17,215
Repayments of borrowings from secured notes payable	(2,749)	(2,688)
Proceeds from issuance of unsecured senior notes payable		544,649
Principal borrowings from unsecured senior line of credit	179,000	248,000
Repayments of borrowings from unsecured senior line of credit	(191,000)	(451,000)
Repayment of unsecured senior bank term loan		(250,000)
Repurchase of unsecured senior convertible notes		(83,801)
Proceeds from issuance of Series E Preferred Stock		124,868
Change in restricted cash related to financings	8,656	(15,955)
Deferred financing costs paid	(46)	(5,300)
Proceeds from exercise of stock options		112
Dividends paid on common stock	(35,687)	(30,386)
Dividends paid on preferred stock	(6,471)	(7,089)
Distributions to redeemable noncontrolling interests		(315)
Contributions by noncontrolling interests		625
Distributions to noncontrolling interests	(427)	(369)
Net cash (used in) provided by financing activities	(31,509)	71,351
Effect of foreign exchange rate changes on cash and cash equivalents	(178)	2,034
Net decrease in cash and cash equivalents	(53,970)	(1,178)
Cash and cash equivalents at beginning of period	140,971	78,539
Cash and cash equivalents at end of period	87,001	77,361
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	9,964	11,976
Non-Cash Investing Activities
Note receivable from sale of real estate	38,820
Changes in accrued capital expenditures	(37,045)	9,396
Alexandria Real Estate Equities, Inc. (Issuer)
Operating Activities
Net income	29,255	32,064
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,473	1,393
Loss on early extinguishment of debt		623
Amortization of loan fees and costs	1,680	1,792
Amortization of debt premiums/discounts	11	81
Deferred rent		17
Stock compensation expense	3,349	3,293
Equity in income related to subsidiaries	(49,807)	(50,008)
Changes in operating assets and liabilities:
Restricted cash	7	(3)
Tenant receivables	(51)	(9)
Deferred leasing costs	(350)	4,266
Other assets	29,445	22
Intercompany receivables and payables	(21)
Accounts payable, accrued expenses, and tenant security deposits	(16,301)	(23,545)
Net cash provided by operating activities	(1,310)	(30,014)
Investing Activities
Proceeds from sale of properties	10,796
Additions to properties		(304)
Investments in subsidiaries	(14,842)	(52,639)
Net cash used in investing activities	(4,046)	(52,943)
Financing Activities
Proceeds from issuance of unsecured senior notes payable		544,649
Principal borrowings from unsecured senior line of credit	179,000	248,000
Repayments of borrowings from unsecured senior line of credit	(191,000)	(451,000)
Repayment of unsecured senior bank term loan		(250,000)
Repurchase of unsecured senior convertible notes		(83,801)
Proceeds from issuance of Series E Preferred Stock		124,868
Deferred financing costs paid	(41)	(5,184)
Proceeds from exercise of stock options		112
Dividends paid on common stock	(35,687)	(30,386)
Dividends paid on preferred stock	(6,471)	(7,089)
Net cash (used in) provided by financing activities	(54,199)	90,169
Net decrease in cash and cash equivalents	(59,555)	7,212
Cash and cash equivalents at beginning of period	98,567	10,608
Cash and cash equivalents at end of period	39,012	17,820
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	3,735	8,855
Non-Cash Investing Activities
Note receivable from sale of real estate	29,820
Changes in accrued capital expenditures		(2,000)
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Operating Activities
Net income	47,173	46,284
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income related to investments		26
Equity in income related to subsidiaries	(47,239)	(45,699)
Gain on sales of investments	(121)	(611)
Loss on sales of investments	187
Investing Activities
Investments in subsidiaries	(30,986)	(43,773)
Additions to investments	(3)	(119)
Proceeds from investments	252	1,149
Net cash used in investing activities	(30,737)	(42,743)
Financing Activities
Transfers due to/from parent company	28,823	44,217
Net cash (used in) provided by financing activities	28,823	44,217
Net decrease in cash and cash equivalents	(1,914)	1,474
Cash and cash equivalents at beginning of period	1,914
Cash and cash equivalents at end of period		1,474
Non-Guarantor Subsidiaries
Operating Activities
Net income	51,815	51,048
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	45,522	42,012
Gain on sale of land parcel		(1,864)
Loss on sale of real estate	340
Amortization of loan fees and costs	706	851
Amortization of debt premiums/discounts	104	98
Amortization of acquired above and below market leases	(830)	(800)
Deferred rent	(6,198)	(8,813)
Equity in income related to subsidiaries	(960)	(914)
Gain on sales of investments	(325)	(1,388)
Loss on sales of investments	199	1
Changes in operating assets and liabilities:
Restricted cash	1,499	865
Tenant receivables	(767)	(1,228)
Deferred leasing costs	(11,407)	(11,277)
Other assets	(36,747)	(2,433)
Intercompany receivables and payables	21
Accounts payable, accrued expenses, and tenant security deposits	5,579	13,541
Net cash provided by operating activities	48,551	79,699
Investing Activities
Proceeds from sale of properties	69,407
Additions to properties	(139,245)	(120,281)
Purchase of properties		(19,946)
Change in restricted cash related to construction projects	(17)	(1,400)
Distribution from unconsolidated real estate entity		22,250
Contributions to unconsolidated real estate entity	(2,074)	(3,914)
Investments in subsidiaries		(1,216)
Additions to investments	(10,360)	(5,319)
Proceeds from investments	1,720	3,636
Net cash used in investing activities	(80,569)	(126,190)
Financing Activities
Principal borrowings from secured notes payable	17,215
Repayments of borrowings from secured notes payable	(2,749)	(2,688)
Transfers due to/from parent company	17,005	53,411
Change in restricted cash related to financings	8,656	(15,955)
Deferred financing costs paid	(5)	(116)
Distributions to redeemable noncontrolling interests		(315)
Contributions by noncontrolling interests		625
Distributions to noncontrolling interests	(427)	(369)
Net cash (used in) provided by financing activities	39,695	34,593
Effect of foreign exchange rate changes on cash and cash equivalents	(178)	2,034
Net decrease in cash and cash equivalents	7,499	(9,864)
Cash and cash equivalents at beginning of period	40,490	67,931
Cash and cash equivalents at end of period	47,989	58,067
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	6,229	3,121
Non-Cash Investing Activities
Note receivable from sale of real estate	9,000
Changes in accrued capital expenditures	(37,045)	11,396
Eliminations
Operating Activities
Net income	(98,006)	(96,621)
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income related to subsidiaries	98,006	96,621
Investing Activities
Investments in subsidiaries	45,828	97,628
Net cash used in investing activities	45,828	97,628
Financing Activities
Transfers due to/from parent company	(45,828)	(97,628)
Net cash (used in) provided by financing activities	$ (45,828)	$ (97,628)