Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Changes in equity
Balance		$ 6,840,793
Net income attributable to common stockholders		100,929
Cash flow hedge loss reclassified to earnings	54,948	57,913
Change in redemption value of redeemable noncontrolling interest		(441)
Noncontrolling interests income allocation		1
Dividends declared to common stockholders		(415,353)
Issuance of common stock, net of withholdings		1,871,799
Amortization of deferred compensation		17,689
Balance	8,473,330	8,473,330
Common stock
Changes in equity
Balance		1,144
Issuance of common stock, net of withholdings		150
Balance	1,294	1,294
Additional paid-in capital
Changes in equity
Balance		7,086,407
Issuance of common stock, net of withholdings		1,872,684
Amortization of deferred compensation		17,689
Balance	8,976,780	8,976,780
Accumulated earnings less dividends
Changes in equity
Balance		(142,329)
Net income attributable to common stockholders		100,929
Change in redemption value of redeemable noncontrolling interest		(441)
Dividends declared to common stockholders		(415,353)
Issuance of common stock, net of withholdings		(1,035)
Balance	(458,229)	(458,229)
Accumulated other comprehensive loss
Changes in equity
Balance		(108,007)
Cash flow hedge loss reclassified to earnings		57,913
Balance	(50,094)	(50,094)
Total AvalonBay stockholders' equity
Changes in equity
Balance		6,837,215
Net income attributable to common stockholders		100,929
Cash flow hedge loss reclassified to earnings		57,913
Change in redemption value of redeemable noncontrolling interest		(441)
Dividends declared to common stockholders		(415,353)
Issuance of common stock, net of withholdings		1,871,799
Amortization of deferred compensation		17,689
Balance	8,469,751	8,469,751
Noncontrolling interests
Changes in equity
Balance		3,578
Noncontrolling interests income allocation		1
Balance	$ 3,579	$ 3,579