Organization and Operation (Details)	Dec. 31, 2012 state sqft property
Real estate properties
Properties owned	3,013
Number of U.S. states where properties are owned	49
Leasable square feet	37,600,000
Crest Net Lease, Inc. (Crest)
Real estate properties
Properties owned	4

The number of states the entity operates in as of the balance sheet date.

No definition available.

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant