Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Changes in equity
Beginning Balance			$ 8,599,727
Net income attributable to common stockholders	241,100	(10,715)	540,929	100,929
Cash flow hedge loss reclassified to earnings	1,546	54,948	4,557	57,913
Noncontrolling interests income allocation			14,221
Change in redemption value of redeemable noncontrolling interest			4,088
Noncontrolling Interest, Decrease from Deconsolidation			17,816
Noncontrolling interests derecognition			(17,816)
Dividends declared to common stockholders			(455,531)
Issuance of common stock, net of withholdings			333,839
Amortization of deferred compensation			21,268
Ending Balance	9,045,282		9,045,282
Common stock
Changes in equity
Beginning Balance			1,294
Issuance of common stock, net of withholdings			26
Ending Balance	1,320		1,320
Additional paid-in capital
Changes in equity
Beginning Balance			8,988,723
Issuance of common stock, net of withholdings			334,207
Amortization of deferred compensation			21,268
Ending Balance	9,344,198		9,344,198
Accumulated earnings less dividends
Changes in equity
Beginning Balance			(345,254)
Net income attributable to common stockholders			540,929
Change in redemption value of redeemable noncontrolling interest			4,088
Dividends declared to common stockholders			(455,531)
Issuance of common stock, net of withholdings			(394)
Ending Balance	(256,162)		(256,162)
Accumulated other comprehensive loss
Changes in equity
Beginning Balance			(48,631)
Cash flow hedge loss reclassified to earnings			4,557
Ending Balance	(44,074)		(44,074)
Total AvalonBay stockholders' equity
Changes in equity
Beginning Balance			8,596,132
Net income attributable to common stockholders			540,929
Cash flow hedge loss reclassified to earnings			4,557
Change in redemption value of redeemable noncontrolling interest			4,088
Dividends declared to common stockholders			(455,531)
Issuance of common stock, net of withholdings			333,839
Amortization of deferred compensation			21,268
Ending Balance	9,045,282		9,045,282
Noncontrolling interests
Changes in equity
Beginning Balance			3,595
Noncontrolling interests income allocation			14,221
Ending Balance	$ 0		$ 0