Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2016

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 June 30, 2016, and December 31, 2015 (in thousands):



			June 30, 2016
Description	Total		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Assets:
Available-for-sale equity securities	$	112,547	$	112,547	$	—	$	—
Interest rate hedge agreements	$	110	$	—	$	110	$	—
Liabilities:
Interest rate hedge agreements	$	12,332	$	—	$	12,332	$	—



			December 31, 2015
Description	Total		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Assets:
Available-for-sale equity securities	$	137,621	$	137,621	$	—	$	—
Interest rate hedge agreements	$	596	$	—	$	596	$	—
Liabilities:
Interest rate hedge agreements	$	4,314	$	—	$	4,314	$	—

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 June 30, 2016, and December 31, 2015, the book and estimated fair values of our available-for-sale equity securities, interest rate hedge agreements, secured notes payable, unsecured senior notes payable, unsecured senior line of credit, and unsecured senior bank term loans were as follows (in thousands):



	June 30, 2016				December 31, 2015
	Book Value		Fair Value		Book Value		Fair Value
Assets:
Available-for-sale equity securities	$	112,547	$	112,547	$	137,621	$	137,621
Interest rate hedge agreements	$	110	$	110	$	596	$	596

Liabilities:
Interest rate hedge agreements	$	12,332	$	12,332	$	4,314	$	4,314
Secured notes payable	$	722,794	$	741,424	$	809,818	$	832,342
Unsecured senior notes payable	$	2,376,713	$	2,513,945	$	2,030,631	$	2,059,855
Unsecured senior line of credit	$	72,000	$	72,098	$	151,000	$	151,450
Unsecured senior bank term loans	$	945,030	$	956,916	$	944,243	$	951,098