Rate used for discounted cash flow analysis of level two fair values of mortgages and notes payable.

No definition available.

Name:	aat_RateUsedForDiscountedCashFlowAnalysisOfLevelTwoFairValuesOfMortgagesAndNotesPayable
Namespace Prefix:	aat_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) during the period in the carrying value of derivative instruments reported as liabilities that are due to be disposed of within one year (or the normal operating cycle, if longer).

+ References

No definition available.

+ Details

Name:	us-gaap_IncreaseDecreaseInDerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

+ Details

Name:	us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Article 5

-Subsection 19, 20, 22

+ Details

Name:	us-gaap_UnsecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) (USD $) In Thousands, unless otherwise specified					3 Months Ended	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum	Sep. 30, 2014 Interest Rate Swap	Sep. 30, 2014 Interest Rate Swap	Sep. 30, 2014 Interest Rate Swap Deferred Credits and Other Liabilities	Jan. 09, 2014 Amended and Restated Credit Facility
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Term loan	$ 100,000	$ 0						$ 100,000
Fair value of interest rate swap	735	0					735
Change in valuation of interest rate swaps					$ 800	$ (735)
Rates of secured notes payable			3.58%	5.44%