Receivables and Other Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and other receivables, net	$ 17,217		$ 17,217		$ 13,317
Tenant note receivable	3,231		3,231		3,287
Deferred financing costs, net	11,888		11,888		11,006
Deferred leasing costs, net	11,912		11,912		10,554
Lease inducements, net	751		751		880
Straight-line rent receivables, net	42,862		42,862		39,095
Prepaid expenses, deposits, equipment and other	5,010		5,010		6,831
Derivative financial instruments - interest rate swaps	4,418		4,418		0
Total	97,289		97,289		84,970
Amortization expense related to deferred leasing costs	593	477	1,158	868
Interest expense related to deferred financing costs	980	877	2,225	2,091
Amortization recorded against rental income related to lease inducements	$ 50	$ 71	$ 100	$ 166
Tenant Note Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate			9.00%