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
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income attributable to common shareholders/unitholders	$ 47,383	$ 36,433
Denominator:
Denominator for basic earnings per share/unit - weighted average shares/units	75,387,332	70,015,856
Effect of Dilutive Securities:
Stock options and non-vested stock	123,000	110,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	75,510,201	70,126,344
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.63	$ 0.52
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.63	$ 0.52
Life Storage LP [Member]
Numerator:
Net income attributable to common shareholders/unitholders	$ 47,383	$ 36,433
Denominator:
Denominator for basic earnings per share/unit - weighted average shares/units	75,387,332	70,015,856
Effect of Dilutive Securities:
Stock options and non-vested stock	123,000	110,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	75,510,201	70,126,344
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.63	$ 0.52
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.63	$ 0.52