Condensed consolidating financial information Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Assets
Investments in real estate, net	$ 7,197,630	$ 6,776,914
Cash and cash equivalents	67,023	57,696	53,839	140,971
Restricted cash	24,245	27,709
Tenant receivables	10,830	9,918
Deferred rent	225,506	190,425
Deferred leasing and financing costs, net	199,835	192,658
Marketable Securities	177,577	140,288
Investments in and advances to affiliates	0	0
Other assets	117,668	134,156
Total assets	8,020,314	7,529,764
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	636,825	708,831
Unsecured senior notes payable	1,747,290	1,048,230
Unsecured senior line of credit	142,000	204,000
Loans Payable to Bank	975,000	1,100,000
Accounts Payable and Accrued Liabilities	504,535	435,342
Dividends payable	57,549	54,420
Total liabilities	4,063,199	3,550,823
Redeemable noncontrolling interests	14,348	14,444
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,875,198	3,916,789
Noncontrolling interests	67,569	47,708
Total equity	3,942,767	3,964,497
Total liabilities, noncontrolling interests, and equity	8,020,314	7,529,764
Alexandria Real Estate Equities, Inc. (Issuer)
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	21,455	14,790	14,667	98,567
Restricted cash	70	55
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	37,486	36,901
Marketable Securities	0	0
Investments in and advances to affiliates	6,812,172	6,299,551
Other assets	19,244	20,226
Total assets	6,890,427	6,371,523
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	1,747,290	1,048,230
Unsecured senior line of credit	142,000	204,000
Loans Payable to Bank	975,000	1,100,000
Accounts Payable and Accrued Liabilities	93,679	48,373
Dividends payable	57,260	54,131
Total liabilities	3,015,229	2,454,734
Redeemable noncontrolling interests	0	0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	3,875,198	3,916,789
Noncontrolling interests	0	0
Total equity	3,875,198	3,916,789
Total liabilities, noncontrolling interests, and equity	6,890,427	6,371,523
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	0	0	0	1,913
Restricted cash	0	0
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	0	0
Marketable Securities	8,147	10,868
Investments in and advances to affiliates	6,291,506	5,823,058
Other assets	0	0
Total assets	6,299,653	5,833,926
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Loans Payable to Bank	0	0
Accounts Payable and Accrued Liabilities	0	0
Dividends payable	0	0
Total liabilities	0	0
Redeemable noncontrolling interests	0	0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	6,299,653	5,833,926
Noncontrolling interests	0	0
Total equity	6,299,653	5,833,926
Total liabilities, noncontrolling interests, and equity	6,299,653	5,833,926
Combined Non- Guarantor Subsidiaries
Assets
Investments in real estate, net	7,197,630	6,776,914
Cash and cash equivalents	45,568	42,906	39,172	40,491
Restricted cash	24,175	27,654
Tenant receivables	10,830	9,918
Deferred rent	225,506	190,425
Deferred leasing and financing costs, net	162,349	155,757
Marketable Securities	169,430	129,420
Investments in and advances to affiliates	129,268	119,421
Other assets	98,424	113,930
Total assets	8,063,180	7,566,345
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	636,825	708,831
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Loans Payable to Bank	0	0
Accounts Payable and Accrued Liabilities	410,856	386,969
Dividends payable	289	289
Total liabilities	1,047,970	1,096,089
Redeemable noncontrolling interests	14,348	14,444
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	6,933,293	6,408,104
Noncontrolling interests	67,569	47,708
Total equity	7,000,862	6,455,812
Total liabilities, noncontrolling interests, and equity	8,063,180	7,566,345
Eliminations
Assets
Investments in real estate, net	0	0
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Tenant receivables	0	0
Deferred rent	0	0
Deferred leasing and financing costs, net	0	0
Marketable Securities	0	0
Investments in and advances to affiliates	(13,232,946)	(12,242,030)
Other assets	0	0
Total assets	(13,232,946)	(12,242,030)
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0	0
Unsecured senior notes payable	0	0
Unsecured senior line of credit	0	0
Loans Payable to Bank	0	0
Accounts Payable and Accrued Liabilities	0	0
Dividends payable	0	0
Total liabilities	0	0
Redeemable noncontrolling interests	0	0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	(13,232,946)	(12,242,030)
Noncontrolling interests	0	0
Total equity	(13,232,946)	(12,242,030)
Total liabilities, noncontrolling interests, and equity	$ (13,232,946)	$ (12,242,030)