Condensed consolidating financial information Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Assets
Investments in real estate, net	$ 7,654,209	$ 7,226,016
Cash and cash equivalents	76,383	86,011	$ 67,023	$ 57,696
Restricted cash	36,993	26,884
Tenant receivables	10,124	10,548
Deferred rent	267,954	234,124
Deferred leasing and financing costs, net	222,343	201,798
Investments	330,570	236,389
Investments in and advances to affiliates	0	0
Other assets	138,768	114,266
Total assets	8,737,344	8,136,036
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	773,619	652,209
Unsecured senior notes payable	1,747,613	1,747,370
Unsecured senior line of credit	843,000	304,000
Unsecured senior bank term loans	950,000	975,000
Accounts payable, accrued expenses, and tenant security deposits	586,594	489,085
Dividends payable	61,340	58,814
Total liabilities	4,962,166	4,226,478
Redeemable noncontrolling interests	14,218	14,315
Alexandria’s stockholders’ equity	3,759,162	3,828,439
Noncontrolling interests	1,798	66,804
Total equity	3,760,960	3,895,243
Total liabilities, noncontrolling interests, and equity	8,737,344	8,136,036
Alexandria Real Estate Equities, Inc. (Issuer)
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	42,738	52,491	21,455	14,790
Restricted cash	95	67
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	31,708	35,462
Investments	0	0
Investments in and advances to affiliates	7,370,645	6,874,866
Other assets	24,470	19,461
Total assets	7,469,656	6,982,347
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	1,747,613	1,747,370
Unsecured senior line of credit	843,000	304,000
Unsecured senior bank term loans	950,000	975,000
Accounts payable, accrued expenses, and tenant security deposits	108,828	69,013
Dividends payable	61,053	58,525
Total liabilities	3,710,494	3,153,908
Redeemable noncontrolling interests	0	0
Alexandria’s stockholders’ equity	3,759,162	3,828,439
Noncontrolling interests	0	0
Total equity	3,759,162	3,828,439
Total liabilities, noncontrolling interests, and equity	7,469,656	6,982,347
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	8	63	0	0
Restricted cash	0	0
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	0	0
Investments	4,711	5,235
Investments in and advances to affiliates	6,685,933	6,295,852
Other assets	0	0
Total assets	6,690,652	6,301,150
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Unsecured senior bank term loans	0	0
Accounts payable, accrued expenses, and tenant security deposits	0	0
Dividends payable	0	0
Total liabilities	0	0
Redeemable noncontrolling interests	0	0
Alexandria’s stockholders’ equity	6,690,652	6,301,150
Noncontrolling interests	0	0
Total equity	6,690,652	6,301,150
Total liabilities, noncontrolling interests, and equity	6,690,652	6,301,150
Combined Non- Guarantor Subsidiaries
Assets
Investments in real estate, net	7,654,209	7,226,016
Cash and cash equivalents	33,637	33,457	45,568	42,906
Restricted cash	36,898	26,817
Tenant receivables	10,124	10,548
Deferred rent	267,954	234,124
Deferred leasing and financing costs, net	190,635	166,336
Investments	325,859	231,154
Investments in and advances to affiliates	136,885	128,943
Other assets	114,298	94,805
Total assets	8,770,499	8,152,200
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	773,619	652,209
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Unsecured senior bank term loans	0	0
Accounts payable, accrued expenses, and tenant security deposits	477,766	420,072
Dividends payable	287	289
Total liabilities	1,251,672	1,072,570
Redeemable noncontrolling interests	14,218	14,315
Alexandria’s stockholders’ equity	7,502,811	6,998,511
Noncontrolling interests	1,798	66,804
Total equity	7,504,609	7,065,315
Total liabilities, noncontrolling interests, and equity	8,770,499	8,152,200
Eliminations
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	0	0	$ 0	$ 0
Restricted cash	0	0
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	0	0
Investments	0	0
Investments in and advances to affiliates	(14,193,463)	(13,299,661)
Other assets	0	0
Total assets	(14,193,463)	(13,299,661)
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Unsecured senior bank term loans	0	0
Accounts payable, accrued expenses, and tenant security deposits	0	0
Dividends payable	0	0
Total liabilities	0	0
Redeemable noncontrolling interests	0	0
Alexandria’s stockholders’ equity	(14,193,463)	(13,299,661)
Noncontrolling interests	0	0
Total equity	(14,193,463)	(13,299,661)
Total liabilities, noncontrolling interests, and equity	$ (14,193,463)	$ (13,299,661)