Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2012

Fair value measurements

Schedule of fair value of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy

The following tables set forth the assets and liabilities that we measure at fair value on a recurring basis by level within the fair value hierarchy as of September 30, 2012, and December 31, 2011 (in thousands):

			September 30, 2012
Description	Total		Quoted Prices in Active Markets for Identical Assets		“Significant Other Observable Inputs”		“Significant Unobservable Inputs”
Assets:
Marketable securities	$	6,563	$	6,563	$	–	$	–
Liabilities:
Interest rate swap agreements	$	25,336	$	–	$	25,336	$	–

			December 31, 2011
Description	Total		Quoted Prices in Active Markets for Identical Assets		“Significant Other Observable Inputs”		“Significant Unobservable Inputs”
Assets:
Marketable securities	$	6,235	$	6,235	$	–	$	–
Liabilities:
Interest rate swap agreements	$	32,980	$	–	$	32,980	$	–

Schedule of the book and fair values of our marketable securities, interest rate swap agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loan

As of September 30, 2012, and December 31, 2011, the book and fair values of our marketable securities, interest rate swap agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loans were as follows (in thousands):

	September 30, 2012						December 31, 2011
	Book Value			Fair Value			Book Value			Fair Value
Marketable securities	$	6,563		$	6,563		$	6,235		$	6,235
Interest rate swap agreements	$	(25,336	)	$	(25,336	)	$	(32,980	)	$	(32,980	)
Secured notes payable	$	(719,350	)	$	(814,637	)	$	(724,305	)	$	(810,128	)
Unsecured senior notes payable	$	(549,794	)	$	(585,016	)	$	(84,959	)	$	(85,221	)
Unsecured senior line of credit	$	(413,000	)	$	(426,757	)	$	(370,000	)	$	(378,783	)
Unsecured senior bank term loans	$	(1,350,000	)	$	(1,362,120	)	$	(1,600,000	)	$	(1,603,917	)