Condensed consolidating financial information Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net income	$ (108,116)	$ 38,430	$ (98,150)	$ 63,438
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	70,169	62,171	141,035	121,091
Loss on early extinguishment of debt	0	189	0	189
Impairment of real estate	156,143	0	185,123	14,510
Equity in losses of unconsolidated real estate JVs	146	(541)	543	(1,115)
Distributions of earnings from unconsolidated real estate joint ventures			181	648
Amortization of loan fees			5,712	5,723
Amortization of debt premiums/discounts			(112)	(182)
Amortization of acquired below-market leases			(1,940)	(1,939)
Deferred rent			(14,568)	(23,193)
Stock compensation expense			11,556	7,744
Equity in earnings of affiliates	0	0	0	0
Investment gains	(14,715)	(7,773)	(20,606)	(13,710)
Investment losses	5,039	5,652	6,821	7,877
Changes in operating assets and liabilities:
Restricted cash			232	110
Tenant receivables			1,277	1,243
Deferred leasing costs			(13,858)	(24,503)
Other assets			(5,931)	(4,921)
Accounts payable, accrued expenses, and tenant security deposits			(25,207)	(1,610)
Net cash provided by operating activities			172,108	151,400
Investing Activities
Proceeds from sale of properties			16,905	92,455
Additions to real estate			(363,061)	(226,302)
Purchase of real estate			0	(137,493)
Deposits for investing activities			(75)	(15,501)
Investments in unconsolidated real estate joint ventures			(5,946)	(3,182)
Investments in subsidiaries			0	0
Additions to investments			(52,366)	(52,738)
Sales of investments			21,543	22,474
Repayment of notes receivable			9,036	4,247
Net cash used in investing activities			(373,964)	(316,040)
Financing Activities
Borrowings from secured notes payable			148,722	42,867
Repayments of borrowings from secured notes payable			(233,168)	(10,075)
Proceeds from issuance of unsecured senior notes payable			348,604	0
Principal borrowings from unsecured senior line of credit			1,486,000	915,000
Repayments of borrowings from unsecured senior line of credit			(1,565,000)	(595,000)
Repayment of unsecured senior bank term loan			0	(25,000)
Transfers to/from parent company			0	0
Change in restricted cash related to financing activities			10,582	(1,520)
Payment of loan fees			(7,927)	(3,559)
Repurchase of Series D cumulative convertible preferred stock			(59,310)	0
Proceeds from the issuance of common stock			367,802	5,052
Dividends on common stock			(115,589)	(106,603)
Dividends on preferred stock			(12,086)	(12,493)
Financing costs paid for sales of noncontrolling interests			(8,093)	0
Contributions from and sale of noncontrolling interests			31,020	340
Distributions to and purchase of noncontrolling interests			(57,998)	(61,890)
Net cash provided by financing activities			333,559	147,119
Effect of foreign exchange rate changes on cash and cash equivalents			(801)	127
Net increase in cash and cash equivalents			130,902	(17,394)
Cash and cash equivalents at beginning of period			125,098	86,011
Cash and cash equivalents at end of period	256,000	68,617	256,000	68,617
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized			37,656	44,332
Non-Cash Investing Activities
Change in accrued construction			59,871	(27,469)
Assumption of secured notes payable in connection with purchase of properties			0	(82,000)
Payable for purchase of noncontrolling interest			0	(52,672)
Redemption of redeemable noncontrolling interests			(5,000)	0
Eliminations
Operating Activities
Net income	171,692	(135,922)	102,359	(234,549)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	0	0	0	0
Loss on early extinguishment of debt		0		0
Impairment of real estate	0	0	0	0
Equity in losses of unconsolidated real estate JVs	0	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures			0	0
Amortization of loan fees			0	0
Amortization of debt premiums/discounts			0	0
Amortization of acquired below-market leases			0	0
Deferred rent			0	0
Stock compensation expense			0	0
Equity in earnings of affiliates	(171,692)	135,922	(102,359)	234,549
Investment gains			0	0
Investment losses			0	0
Changes in operating assets and liabilities:
Restricted cash			0	0
Tenant receivables			0	0
Deferred leasing costs			0	0
Other assets			0	0
Accounts payable, accrued expenses, and tenant security deposits			0	0
Net cash provided by operating activities			0	0
Investing Activities
Proceeds from sale of properties			0	0
Additions to real estate			0	0
Purchase of real estate				0
Deposits for investing activities			0	0
Investments in unconsolidated real estate joint ventures			0	0
Investments in subsidiaries			562,850	283,561
Additions to investments			0	0
Sales of investments			0	0
Repayment of notes receivable			0	0
Net cash used in investing activities			562,850	283,561
Financing Activities
Borrowings from secured notes payable			0	0
Repayments of borrowings from secured notes payable			0	0
Proceeds from issuance of unsecured senior notes payable			0
Principal borrowings from unsecured senior line of credit			0	0
Repayments of borrowings from unsecured senior line of credit			0	0
Repayment of unsecured senior bank term loan				0
Transfers to/from parent company			(562,850)	(283,561)
Change in restricted cash related to financing activities			0	0
Payment of loan fees			0	0
Repurchase of Series D cumulative convertible preferred stock			0
Proceeds from the issuance of common stock			0	0
Dividends on common stock			0	0
Dividends on preferred stock			0	0
Financing costs paid for sales of noncontrolling interests			0
Contributions from and sale of noncontrolling interests			0	0
Distributions to and purchase of noncontrolling interests			0	0
Net cash provided by financing activities			(562,850)	(283,561)
Effect of foreign exchange rate changes on cash and cash equivalents			0	0
Net increase in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized			0	0
Non-Cash Investing Activities
Change in accrued construction			0	0
Assumption of secured notes payable in connection with purchase of properties				0
Payable for purchase of noncontrolling interest				0
Redemption of redeemable noncontrolling interests			0
Alexandria Real Estate Equities, Inc. (Issuer)
Operating Activities
Net income	(111,616)	38,167	(105,680)	62,683
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,661	1,469	3,275	2,716
Loss on early extinguishment of debt		189		189
Impairment of real estate	0	0	0	0
Equity in losses of unconsolidated real estate JVs	0	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures			0	0
Amortization of loan fees			3,898	3,852
Amortization of debt premiums/discounts			218	161
Amortization of acquired below-market leases			0	0
Deferred rent			0	0
Stock compensation expense			11,556	7,744
Equity in earnings of affiliates	77,362	(69,406)	39,347	(121,526)
Investment gains			0	0
Investment losses			0	0
Changes in operating assets and liabilities:
Restricted cash			(3)	(7)
Tenant receivables			0	0
Deferred leasing costs			0	0
Other assets			(4,638)	(6,208)
Accounts payable, accrued expenses, and tenant security deposits			10,343	10,367
Net cash provided by operating activities			(41,684)	(40,029)
Investing Activities
Proceeds from sale of properties			0	0
Additions to real estate			0	0
Purchase of real estate				0
Deposits for investing activities			0	0
Investments in unconsolidated real estate joint ventures			0	0
Investments in subsidiaries			(268,460)	(199,541)
Additions to investments			0	0
Sales of investments			0	0
Repayment of notes receivable			0	0
Net cash used in investing activities			(268,460)	(199,541)
Financing Activities
Borrowings from secured notes payable			0	0
Repayments of borrowings from secured notes payable			0	0
Proceeds from issuance of unsecured senior notes payable			348,604
Principal borrowings from unsecured senior line of credit			1,486,000	915,000
Repayments of borrowings from unsecured senior line of credit			(1,565,000)	(595,000)
Repayment of unsecured senior bank term loan				(25,000)
Transfers to/from parent company			(27,824)	43,457
Change in restricted cash related to financing activities			0	0
Payment of loan fees			(3,866)	(2,104)
Repurchase of Series D cumulative convertible preferred stock			(59,310)
Proceeds from the issuance of common stock			367,802	5,052
Dividends on common stock			(115,589)	(106,603)
Dividends on preferred stock			(12,086)	(12,493)
Financing costs paid for sales of noncontrolling interests			0
Contributions from and sale of noncontrolling interests			0	0
Distributions to and purchase of noncontrolling interests			0	0
Net cash provided by financing activities			418,731	222,309
Effect of foreign exchange rate changes on cash and cash equivalents			0	0
Net increase in cash and cash equivalents			108,587	(17,261)
Cash and cash equivalents at beginning of period			31,982	52,491
Cash and cash equivalents at end of period	140,569	35,230	140,569	35,230
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized			28,404	33,695
Non-Cash Investing Activities
Change in accrued construction			0	0
Assumption of secured notes payable in connection with purchase of properties				0
Payable for purchase of noncontrolling interest				(52,672)
Redemption of redeemable noncontrolling interests			0
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Operating Activities
Net income	(92,465)	65,246	(61,790)	110,795
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	0	0	0	0
Loss on early extinguishment of debt		0		0
Impairment of real estate	0	0	0	0
Equity in losses of unconsolidated real estate JVs	0	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures			0	0
Amortization of loan fees			0	0
Amortization of debt premiums/discounts			0	0
Amortization of acquired below-market leases			0	0
Deferred rent			0	0
Stock compensation expense			0	0
Equity in earnings of affiliates	92,493	(65,246)	61,814	(110,836)
Investment gains			(322)	0
Investment losses			11	41
Changes in operating assets and liabilities:
Restricted cash			0	0
Tenant receivables			0	0
Deferred leasing costs			0	0
Other assets			0	0
Accounts payable, accrued expenses, and tenant security deposits			(508)	0
Net cash provided by operating activities			(795)	0
Investing Activities
Proceeds from sale of properties			0	0
Additions to real estate			0	0
Purchase of real estate				0
Deposits for investing activities			0	0
Investments in unconsolidated real estate joint ventures			0	0
Investments in subsidiaries			(288,584)	(82,309)
Additions to investments			0	0
Sales of investments			845	6
Repayment of notes receivable			0	0
Net cash used in investing activities			(287,739)	(82,303)
Financing Activities
Borrowings from secured notes payable			0	0
Repayments of borrowings from secured notes payable			0	0
Proceeds from issuance of unsecured senior notes payable			0
Principal borrowings from unsecured senior line of credit			0	0
Repayments of borrowings from unsecured senior line of credit			0	0
Transfers to/from parent company			288,534	82,240
Change in restricted cash related to financing activities			0	0
Payment of loan fees			0	0
Repurchase of Series D cumulative convertible preferred stock			0
Proceeds from the issuance of common stock			0
Dividends on common stock			0	0
Dividends on preferred stock			0	0
Financing costs paid for sales of noncontrolling interests			0
Contributions from and sale of noncontrolling interests			0	0
Distributions to and purchase of noncontrolling interests			0	0
Net cash provided by financing activities			288,534	82,240
Effect of foreign exchange rate changes on cash and cash equivalents			0	0
Net increase in cash and cash equivalents			0	(63)
Cash and cash equivalents at beginning of period			0	63
Cash and cash equivalents at end of period	0	0	0	0
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized			0	0
Non-Cash Investing Activities
Change in accrued construction			0	0
Assumption of secured notes payable in connection with purchase of properties				0
Payable for purchase of noncontrolling interest				0
Redemption of redeemable noncontrolling interests			0
Combined Non- Guarantor Subsidiaries
Operating Activities
Net income	(75,727)	70,939	(33,039)	124,509
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	68,508	60,702	137,760	118,375
Loss on early extinguishment of debt		0		0
Impairment of real estate	156,143	0	185,123	14,510
Equity in losses of unconsolidated real estate JVs	146	(541)	543	(1,115)
Distributions of earnings from unconsolidated real estate joint ventures			181	648
Amortization of loan fees			1,814	1,871
Amortization of debt premiums/discounts			(330)	(343)
Amortization of acquired below-market leases			(1,940)	(1,939)
Deferred rent			(14,568)	(23,193)
Stock compensation expense			0	0
Equity in earnings of affiliates	1,837	(1,270)	1,198	(2,187)
Investment gains			(20,284)	(13,710)
Investment losses			6,810	7,836
Changes in operating assets and liabilities:
Restricted cash			235	117
Tenant receivables			1,277	1,243
Deferred leasing costs			(13,858)	(24,503)
Other assets			(1,293)	1,287
Accounts payable, accrued expenses, and tenant security deposits			(35,042)	(11,977)
Net cash provided by operating activities			214,587	191,429
Investing Activities
Proceeds from sale of properties			16,905	92,455
Additions to real estate			(363,061)	(226,302)
Purchase of real estate				(137,493)
Deposits for investing activities			(75)	(15,501)
Investments in unconsolidated real estate joint ventures			(5,946)	(3,182)
Investments in subsidiaries			(5,806)	(1,711)
Additions to investments			(52,366)	(52,738)
Sales of investments			20,698	22,468
Repayment of notes receivable			9,036	4,247
Net cash used in investing activities			(380,615)	(317,757)
Financing Activities
Borrowings from secured notes payable			148,722	42,867
Repayments of borrowings from secured notes payable			(233,168)	(10,075)
Proceeds from issuance of unsecured senior notes payable			0
Principal borrowings from unsecured senior line of credit			0	0
Repayments of borrowings from unsecured senior line of credit			0	0
Transfers to/from parent company			302,140	157,864
Change in restricted cash related to financing activities			10,582	(1,520)
Payment of loan fees			(4,061)	(1,455)
Repurchase of Series D cumulative convertible preferred stock			0
Proceeds from the issuance of common stock			0
Dividends on common stock			0	0
Dividends on preferred stock			0	0
Financing costs paid for sales of noncontrolling interests			(8,093)
Contributions from and sale of noncontrolling interests			31,020	340
Distributions to and purchase of noncontrolling interests			(57,998)	(61,890)
Net cash provided by financing activities			189,144	126,131
Effect of foreign exchange rate changes on cash and cash equivalents			(801)	127
Net increase in cash and cash equivalents			22,315	(70)
Cash and cash equivalents at beginning of period			93,116	33,457
Cash and cash equivalents at end of period	$ 115,431	$ 33,387	115,431	33,387
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized			9,252	10,637
Non-Cash Investing Activities
Change in accrued construction			59,871	(27,469)
Assumption of secured notes payable in connection with purchase of properties				(82,000)
Payable for purchase of noncontrolling interest				$ 0
Redemption of redeemable noncontrolling interests			$ (5,000)