Components of Rental Income and Expense (Components Of Rental Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components Of Rental Income and Expense [Abstract]
Repairs and maintenance	$ 64,942	$ 62,420	$ 55,444
Utilities	24,968	23,003	20,499
Management fees and costs	20,823	18,639	17,416
Payroll	13,832	12,673	11,554
Marketing	8,520	9,046	9,532
Insurance	7,758	7,875	6,462
Ground rent	2,561	2,540	1,952
Bad debt expense	2,375	1,168	2,021
Other operating	12,547	10,229	10,537
Total rental expenses	$ 158,326	$ 147,593	$ 135,417