BORROWING ARRANGEMENTS - Unsecured Borrowings - $700 Million Unsecured Credit Facility (Narrative) (Detail 2) (USD $)	12 Months Ended										0 Months Ended	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2011 2010 Credit Facility	Dec. 31, 2012 2011 Credit Facility	Dec. 06, 2012 Unsecured Borrowings	Aug. 16, 2011 Unsecured Borrowings 2010 Credit Facility	Aug. 16, 2011 Unsecured Borrowings 2011 Credit Facility	Dec. 31, 2011 Unsecured Borrowings 2011 Credit Facility	Dec. 06, 2012 Unsecured Borrowings 2011 Credit Facility	Dec. 31, 2012 Unsecured Borrowings Credit Facility 2012
Borrowing Arrangements [Line Items]
Credit facility, borrowing capacity									$ 700,000,000		$ 475,000,000
Line of credit facility terminated							320,000,000	475,000,000		320,000,000			475,000,000
Credit facility, maturity period (in years)											4 years
Revolving line of credit	258,000,000		272,500,000									272,500,000		258,000,000
Credit facility available for future borrowing												202,500,000		442,000,000
Weighted average annual interest rate												2.85%		1.81%
Write-offs associated with deferred costs	$ 3,024,000	[1],[2],[3]	$ 3,055,000	[1],[2],[3]	$ 8,231,000	[1],[2],[3]	$ 3,100,000	$ 2,500,000				$ 2,500,000

[1] In 2010, we wrote-off: (a) $3.5 million associated with the termination of our $200 million 2009 Credit Facility, (b) $2.2 million associated with the termination of a $100 million GECC term loan and (c) $2.6 million associated with the tender offer and retirement of our outstanding $310 million 7% Senior Notes due 2014.

[2] In 2012, we wrote-off: (a) $2.2 million deferred financing costs associated with the tender offer and redemption of our $175 million 7% 2016 Notes; and (b) $2.5 million deferred financing costs associated with the termination of our $475 million 2011 Credit Facility. These costs were offset by a $1.7 million gain resulting from the write-off of unamortized premium on the four HUD loans that were paid off in the second quarter of 2012.

[3] In 2011, we terminated our $320 million 2010 Credit Facility and wrote-off deferred financing costs of $3.1 million.