Income taxes (Details)	12 Months Ended
Dec. 31, 2013
Income Tax Disclosure [Abstract]
Minimum percentage of taxable income to be distributed	100.00%
The Company generally distributes this percentage or more of its taxable income	100.00%

Represents the percentage of annual taxable income which must be distributed to stockholders in order to comply with requirements of the federal tax law for treatment as a real estate investment trust.

No definition available.

Name:	are_MinimumPercentageOfTaxableIncomeToBeDistributed
Namespace Prefix:	are_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration