Operating Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 property state	Dec. 31, 2011	Dec. 31, 2010
Operating leases
Number of properties owned	3,013
Number of U.S. states where properties are owned	49
Single-tenant properties	2,996
Single-tenant properties (as a percent)	99.40%
Multi-tenant properties	17
Vacant properties available for lease or sale	84
Percentage rents	$ 2,100,000	$ 1,400,000	$ 1,400,000
Percentage rents including amounts recorded to discontinued operations	124,000	60,000	104,000
Minimum future annual rents to be received on the operating leases
2013	526,616,000
2014	512,274,000
2015	497,075,000
2016	483,389,000
2017	464,982,000
Thereafter	3,399,120,000
Total	$ 5,883,456,000
Crest
Operating leases
Number of properties owned	4