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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income attributable to common shareholders/unitholders	$ 39,274	$ 19,355	$ 73,163	$ 39,785
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,480,907	46,364,890	46,466,700	46,334,729
Effect of Dilutive Securities:
Stock options and non-vested stock	95,000	113,000	90,000	113,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,576,352	46,477,680	46,556,512	46,448,286
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.84	$ 0.42	$ 1.57	$ 0.86
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.84	$ 0.42	$ 1.57	$ 0.86
Life Storage LP [Member]
Numerator:
Net income attributable to common shareholders/unitholders	$ 39,274	$ 19,355	$ 73,163	$ 39,785
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,480,907	46,364,890	46,466,700	46,334,729
Effect of Dilutive Securities:
Stock options and non-vested stock	95,000	113,000	90,000	113,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,576,352	46,477,680	46,556,512	46,448,286
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.84	$ 0.42	$ 1.57	$ 0.86
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.84	$ 0.42	$ 1.57	$ 0.86