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, 2018	Mar. 31, 2017
Numerator:
Net income attributable to common shareholders/unitholders	$ 33,889	$ 20,429
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,452,492	46,304,568
Effect of Dilutive Securities:
Stock options and non-vested stock	85,000	114,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,536,672	46,418,891
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.73	$ 0.44
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.73	$ 0.44
Life Storage LP [Member]
Numerator:
Net income attributable to common shareholders/unitholders	$ 33,889	$ 20,429
Denominator:
Denominator for basic earnings per share/unit – weighted average shares/units	46,452,492	46,304,568
Effect of Dilutive Securities:
Stock options and non-vested stock	85,000	114,000
Denominator for diluted earnings per share/unit - adjusted weighted average shares/units and assumed conversion	46,536,672	46,418,891
Basic earnings per common share/unit attributable to common shareholders/unitholders	$ 0.73	$ 0.44
Diluted earnings per common share/unit attributable to common shareholders/unitholders	$ 0.73	$ 0.44