Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues
Rental income	$ 69,953	$ 59,562
Other operating income	5,504	4,317
Total operating revenues	75,457	63,879
Expenses
Property operations and maintenance	17,064	15,125
Real estate taxes	8,066	6,419
General and administrative	9,956	8,793
Acquisition costs	2,778	486
Operating leases of storage facilities	1,997
Depreciation and amortization	11,942	11,202
Total operating expenses	51,803	42,025
Income from operations	23,654	21,854
Other income (expenses)
Interest expense	(7,343)	(8,457)
Interest income	6
Gain on sale of real estate		421
Equity in income of joint ventures	458	386
Income from continuing operations	16,775	14,204
Income from discontinued operations		168
Net income	16,775	14,372
Net income attributable to noncontrolling interest	(102)	(92)
Net income attributable to common shareholders	$ 16,673	$ 14,280
Earnings per common share attributable to common shareholders - basic
Continuing operations	$ 0.51	$ 0.46
Discontinued operations		$ 0.01
Earnings per share-basic	$ 0.51	$ 0.47
Earnings per common share attributable to common shareholders - diluted
Continuing operations	$ 0.51	$ 0.46
Discontinued operations		$ 0.01
Earnings per share-diluted	$ 0.51	$ 0.47
Common shares used in basic earnings per share calculation	32,383,996	30,488,853
Common shares used in diluted earnings per share calculation	32,538,429	30,654,495
Dividends declared per common share	$ 0.68	$ 0.48