Credit Facility And Notes Payable (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 02, 2013 Term Loan [Member]	Feb. 21, 2014 Term Loan [Member]	Dec. 31, 2013 Term Loan [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2013 Minimum [Member]	Feb. 25, 2014 Subsequent Event [Member]	Feb. 25, 2014 Subsequent Event [Member] Term Loan [Member]	Oct. 18, 2013 PSB Loan [Member]	Oct. 02, 2013 PSB Loan [Member]
Short-term Debt [Line Items]
Credit Facility borrowing capacity	$ 300,000,000
Expiration of Credit Facility	Mar. 21, 2017
Interest rate spread (LIBOR)							1.50%	0.90%
Interest at period end spread (LIBOR)	0.90%
Quarterly facility fee	0.125%						0.30%	0.125%
Outstanding borrowings on Credit Facility	50,100,000	133,000,000							0
Reduction in borrowing capacity to amount of letters of credit	15,100,000	15,300,000
Term loan period				1 year
Term loan, maturity date				Dec. 02, 2014
Term loan issuance amount				700,000,000
Term loan	700,000,000					700,000,000				600,000,000
Term loan, interest rate					1.065%	1.065%
Loan origination costs				1,900,000
Loan origination costs, amortization period				1 year
Unamortized loan costs						1,800,000
Mortgage debt assumed	6,100,000		9,700,000
Assumed note balances	5,700,000		8,800,000
Assumed debt, fair value, percent	3.70%		2.90%
Stated note rate	6.20%		5.50%								1.388%
Initial premium	400,000		900,000
Amount borrowed												100,000,000
Cash paid for interest expense	10,400,000	21,700,000	27,600,000
Interest capitalized as real estate		$ 400,000	$ 400,000