The table below presents certain of our assets and liabilities measured at fair value during 2011, categorized by the level of inputs used in the valuation of each asset and liability:

				Fair Value at Reporting Date Using

Description	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Recurring Fair Value Measurements:
Effective portion of interest rate contracts⁽¹⁾	$	(15,796	)	$	—	$	(15,796	)	$	—
Non-Recurring Fair Value Measurements:
Long-lived assets held and used⁽²⁾	$	32,718		$	—	$	—		$	32,718

⁽¹⁾: The fair value of our interest rate swap contracts is determined using the net discounted cash flows of the expected cash flows of each derivative based on the market based interest rate curve (level 2 inputs) and adjusted for our credit spread and the actual and estimated credit spreads of the counterparties (level 3 inputs). Although we have determined that the majority of the inputs used to value our derivatives fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize level 3 inputs, such as estimates of current credit spreads, to evaluate the likelihood of default by us and the counterparties. As of December 31, 2011, we have assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and have determined that the credit valuation adjustments are not significant to the overall valuation of our derivatives. As a result, we have determined that our derivative valuations in their entirety are classified as level 2 inputs in the fair value hierarchy.
⁽²⁾: Long-lived assets held and used consist of six office properties and 20 industrial properties that were written down from their carrying value of $42,322 to their estimated fair value of $32,718, resulting in an impairment charge of $9,604 in our Other Markets segment for the year ended December 31, 2011. The fair value for these properties was estimated as of November 30, 2011 and is not indicative of estimated market value as of December 31, 2011. We used broker information and comparable sales transactions for 21 properties and the sum of their expected future discounted cash flows for five properties (level 3 inputs) less estimated closing costs to determine the fair value of these properties. We estimate aggregate future cash flows expected to be generated by each property based on a number of factors such as market rents, operating expenses, discount rates and capitalization rates. These factors are generally based on our experience in local real estate markets and the effects of current market conditions.

We are exposed to certain risks relating to our ongoing business operations, including the effect of changes in foreign currency exchange rates and interest rates. The only risk currently managed by using our derivative instruments is a part of our interest rate risk. Although we have not done so as of December 31, 2011 and have no present intention to do so, we may manage our Australian currency exchange exposure by borrowing in Australian dollars or using derivative instruments in the future, depending on the relative significance of our business activities in Australia at that time. We have interest rate swap agreements to manage our interest rate risk exposure on $175,000 of mortgage notes due 2019, which require interest at a spread over LIBOR. The interest rate swap agreements utilized by us qualify as cash flow hedges and effectively modify our exposure to interest rate risk by converting our floating interest rate debt to a fixed interest rate basis for this loan through December 1, 2016, thus reducing the impact of interest rate changes on future interest expense. These agreements involve the receipt of floating interest rate amounts in exchange for fixed rate interest payments over the life of the agreements without an exchange of the underlying principal amount. The fair value of our derivative instruments decreased by $8,840 and $9,501 during the years ended December 31, 2011 and 2010, respectively, based primarily on changes in market interest rates. As of December 31, 2011 and 2010, the fair value of these derivative instruments included in accounts payable and accrued expenses and cumulative other comprehensive (loss) income in our consolidated balance sheets totaled ($15,796) and ($6,956), respectively. We may enter additional interest rate swaps or hedge agreements to manage some of our additional interest rate risk associated with our floating rate borrowings.

In addition to the assets and liabilities described in the above table, our financial instruments include our cash and cash equivalents, rents receivable, equity investments, investment in direct financing lease receivable, restricted cash, revolving credit facility, senior notes and mortgage notes payable, accounts payable and accrued expenses, rent collected in advance, security deposits and amounts due to related persons. At December 31, 2011 and 2010, the fair values of these additional financial instruments were not materially different from their carrying values, except as follows:

At December 31, 2011 and 2010, the fair values of our equity investment in GOV are based on quoted market prices of $22.55 and $26.79, respectively. The fair values of our senior notes and mortgage notes payable are based on estimates using discounted cash flow analyses and currently prevailing interest rates adjusted by credit risk spreads.

Other financial instruments that potentially subject us to concentrations of credit risk consist principally of rents receivable; however, no single tenant of ours is responsible for more than 3% of our total rents.

We maintain derivative financial instruments, including interest rate swaps, with major financial institutions and monitor the amount of credit exposure to any one counterparty.