Earnings Per Share and Earnings Per Unit - Computation of Basic and Diluted Earnings Per Common Share/Unit (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income attributable to common shareholders/unitholders	$ 40,742	$ 34,454	$ 39,274	$ 33,889	$ 75,196	$ 73,163
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,582,235		46,480,907		46,573,541	46,466,700
Effect of Dilutive Securities:
Stock options and non-vested stock	49,000		95,000		60,000	90,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,631,214		46,576,352		46,633,957	46,556,512
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.87		$ 0.84		$ 1.61	$ 1.57
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.87		$ 0.84		$ 1.61	$ 1.57
Life Storage LP [Member]
Numerator:
Net income attributable to common shareholders/unitholders	$ 40,742	$ 34,454	$ 39,274	$ 33,889	$ 75,196	$ 73,163
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,582,235		46,480,907		46,573,541	46,466,700
Effect of Dilutive Securities:
Stock options and non-vested stock	49,000		95,000		60,000	90,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,631,214		46,576,352		46,633,957	46,556,512
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.87		$ 0.84		$ 1.61	$ 1.57
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.87		$ 0.84		$ 1.61	$ 1.57