Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investment in storage facilities:
Land	$ 283,363	$ 263,407
Building, equipment, and construction in progress	1,379,550	1,275,188
Real estate investment property, at cost, total	1,662,913	1,538,595
Less: accumulated depreciation	(319,941)	(292,722)
Investment in storage facilities, net	1,342,972	1,245,873
Cash and cash equivalents	5,419	7,321
Accounts receivable	3,272	2,938
Receivable from unconsolidated joint ventures	676	589
Investment in unconsolidated joint ventures	34,524	31,939
Prepaid expenses	4,975	3,939
Other assets	5,510	7,373
Net assets of discontinued operations		43,702
Total Assets	1,397,348	1,343,674
Liabilities
Line of credit	26,000	46,000
Term notes	575,000	575,000
Accounts payable and accrued liabilities	29,797	31,414
Deferred revenue	6,381	6,084
Fair value of interest rate swap agreements	16,493	10,748
Mortgages payable	4,295	4,423
Total Liabilities	657,966	673,669
Noncontrolling redeemable Operating Partnership Units at redemption value	11,811	14,466
Shareholders' Equity
Common stock $.01 par value, 100,000,000 shares authorized, 30,432,720 shares outstanding (28,952,356 at December 31, 2011)	316	301
Additional paid-in capital	942,327	862,467
Dividends in excess of net income	(171,673)	(169,799)
Accumulated other comprehensive loss	(16,224)	(10,255)
Treasury stock at cost, 1,171,886 shares	(27,175)	(27,175)
Total Shareholders' Equity	727,571	655,539
Total Liabilities and Shareholders' Equity	$ 1,397,348	$ 1,343,674