Sales of Real Estate and Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 properties	Dec. 31, 2012 properties	Dec. 31, 2011
Discontinued Operations and Disposal Groups [Abstract]
Aggregate gross disposition price	$ 75,519	$ 142,022	$ 124,039
Aggregate Gain on Sales of Properties	24,472	13,291	6,557
Debt satisfaction gains (charges), net	8,955	(178)	(606)
Properties classified as held-for-sale (in # of properties)	0	0
Total gross revenues	7,577	22,591	44,247
Pre-tax net income (loss), including gains on sales	$ 19,746	$ 1,807	$ (87,533)