Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating Activities
Net income	$ 11,269,000	$ 8,700,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,245,000	8,625,000
Amortization of deferred financing fees	208,000	257,000
Equity in income of joint ventures	(68,000)	(40,000)
Distributions from unconsolidated joint venture	337,000	188,000
Non-vested stock earned	600,000	332,000
Stock option expense	51,000	69,000
Changes in assets and liabilities (excluding the effects of acquisitions):
Accounts receivable	(347,000)	463,000
Prepaid expenses	(2,653,000)	(1,947,000)
Accounts payable and other liabilities	(11,705,000)	(5,574,000)
Deferred revenue	522,000	109,000
Net cash provided by operating activities	8,459,000	11,182,000
Investing Activities
Acquisitions of storage facilities
Improvements, equipment additions, and construction in progress	(4,361,000)	(3,541,000)
Investment in unconsolidated joint ventures	(2,270,000)
(Advances) reimbursement of advances to joint ventures	(421,000)	21,000
Property deposits	125,000	(1,050,000)
Net cash used in investing activities	(6,927,000)	(4,570,000)
Financing Activities
Net proceeds from sale of common stock	773,000	340,000
Proceeds from line of credit	17,000,000	12,000,000
Repayments of line of credit		(6,000,000)
Financing costs		(312,000)
Dividends paid-common stock	(13,027,000)	(12,444,000)
Distributions to noncontrolling interest holders	(152,000)	(493,000)
Mortgage principal payments	(42,000)	(610,000)
Net cash provided by (used in) financing activities	4,552,000	(7,519,000)
Net increase (decrease) in cash	6,084,000	(907,000)
Cash at beginning of period	7,321,000	5,766,000
Cash at end of period	13,405,000	4,859,000
Supplemental cash flow information
Cash paid for interest, net of interest capitalized	$ 8,512,000	$ 6,624,000