Component of Rental Income and Expense Components of Rental Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Rental Income [Line Items]
Cost reimbursement	$ 30,796	$ 29,052	$ 27,583
Percentage rent	2,834	3,107	2,655
Hotel revenue	38,191	33,911	35,137
Other	1,492	1,681	1,688
Total rental income	261,887	246,078	242,757
Total Retail
Rental Income [Line Items]
Minimum rents	72,999	70,573	69,374
Total Office
Rental Income [Line Items]
Minimum rents	87,125	82,018	81,845
Total Multifamily
Rental Income [Line Items]
Minimum rents	18,137	15,732	14,926
Total Mixed-Use
Rental Income [Line Items]
Minimum rents	$ 10,313	$ 10,004	$ 9,549