Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Real estate properties:
Land	$ 164,649		$ 161,875
Buildings, improvements and lease intangibles	2,613,069		2,625,538
Personal property	19,208		19,100
Land held for development	17,054		25,171
Real estate properties, Total	2,813,980		2,831,684
Less accumulated depreciation	(597,434)		(586,725)
Total real estate properties, net	2,216,546		2,244,959
Cash and cash equivalents	94,171		6,776
Mortgage notes receivable	190,134	[1]	162,191	[1]
Assets held for sale and discontinued operations, net	22,297		3,337
Other assets, net	132,102		122,709
Total assets	2,655,250		2,539,972
Liabilities:
Notes and bonds payable	1,415,119	[2]	1,293,044	[2]
Accounts payable and accrued liabilities	45,534		65,678
Liabilities of discontinued operations	86		131
Other liabilities	57,895		60,175
Total liabilities	1,518,634		1,419,028
Commitments and contingencies
Equity:
Preferred stock, $.01 par value; 50,000 shares authorized; none issued and outstanding	0		0
Common stock, $.01 par value; 150,000 shares authorized; 89,217 and 87,514 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	892		875
Additional paid-in capital	2,142,346		2,100,297
Accumulated other comprehensive loss	(2,092)		(2,092)
Cumulative net income attributable to common stockholders	800,417		801,416
Cumulative dividends	(1,806,298)		(1,779,552)
Total stockholders’ equity	1,135,265		1,120,944
Noncontrolling interests	1,351		0
Total equity	1,136,616		1,120,944
Total liabilities and equity	$ 2,655,250		$ 2,539,972

[1] Level 2 - Fair value based on quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which significant inputs and significant value drivers are observable in active markets.

[2] Level 3 - Fair value derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.