Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 404,047	$ 402,793	$ 194,204
Unrealized gains (losses) on available-for-sale equity securities:
Unrealized holding gains (losses) arising during the period	0	0	24,360
Reclassification adjustment for losses included in net income	0	0	6,118
Unrealized gains (losses) on available-for-sale equity securities, net	0	0	30,478
Unrealized gains (losses) on interest rate hedge agreements:
Unrealized interest rate hedge (losses) gains arising during the period	(1,763)	1,622	2,837
Reclassification adjustment for amortization (income) expense to interest expense included in net income	(1,777)	(4,941)	1,915
Reclassification of losses related to terminated interest rate hedge instruments to interest expense included in net (loss) income	1,702	0	0
Unrealized gains (losses) on interest rate swap agreements, net	(1,838)	(3,319)	4,752
Unrealized gains (losses) on foreign currency translations:
Unrealized foreign currency translation gains (losses) arising during the period	2,524	(7,369)	7,774
Reclassification adjustment for cumulative foreign currency translation losses included in net income (loss) upon sale or liquidation	0	0	1,599
Unrealized gains (losses) on foreign currency translation, net	2,524	(7,369)	9,373
Total other comprehensive income (loss)	686	(10,688)	44,603
Comprehensive income (loss)	404,733	392,105	238,807
Less: comprehensive income attributable to noncontrolling interests	(40,882)	(23,481)	(25,045)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.'s stockholders	$ 363,851	$ 368,624	$ 213,762