CONSOLIDATED STATEMENTS OF CAPITAL (LP cube) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended	12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Dec. 31, 2019
Increase (Decrease) in Partners' Capital
Balance of Noncontrolling Interests in the Operating Partnership		$ 62,088			$ 62,088
Contributions from noncontrolling interests in subsidiaries				$ 4,828
Distributions paid to noncontrolling interests in subsidiaries	$ (42)	(59)	$ (8)	(66)
Acquisition of noncontrolling interest in subsidiary			(27,618)	(10,000)
Adjustment for Operating Partnership interests of third parties	(615)	7,976	(2,713)	(6,681)	7,400	$ 5,900
Net income (loss)	38,543	37,934	49,379	35,428
Other comprehensive income, net	20	20	20	240
Balance of Noncontrolling Interests in the Operating Partnership	51,407				51,407	62,088
Noncontrolling Interests in Operating Partnership
Increase (Decrease) in Partners' Capital
Balance of Noncontrolling Interests in the Operating Partnership	53,845	62,088	60,414	55,819	62,088	55,819
Adjustment for Operating Partnership interests of third parties	615	(7,976)	2,713	6,681
Net income (loss)	389	383	499	358
Other comprehensive income, net				2
Balance of Noncontrolling Interests in the Operating Partnership	51,407	53,845	62,385	60,414	51,407	62,088
Cubesmart, L P and Subsidiaries
Increase (Decrease) in Partners' Capital
Balance	1,790,290	1,807,336	1,708,560	1,716,449	1,807,336	1,716,449
Balance of Noncontrolling Interests in the Operating Partnership		62,088			62,088
Contributions from noncontrolling interests in subsidiaries				4,828
Distributions paid to noncontrolling interests in subsidiaries	(42)	(59)	(8)	(66)
Issuance of common OP units	(70)	(118)
Acquisition of noncontrolling interest in subsidiary			(27,618)	(10,000)
Issuance of common OP units			110,521	24,580
Conversion from OP units to shares	2,824		644	1,842
Exercise of OP unit options	135		962	1,049
Amortization of restricted OP units	1,249	710	1,231	798
OP unit compensation expense	464	530	439	468
Adjustment for Operating Partnership interests of third parties	(615)	7,976	(2,713)	(6,681)
Net income (loss)	38,543	37,934	49,379	35,428
Other comprehensive income, net	20	20	20	240
Common OP unit distributions	(64,081)	(64,039)	(61,431)	(60,375)
Balance	1,768,717	1,790,290	1,779,986	1,708,560	1,768,717	1,807,336
Balance of Noncontrolling Interests in the Operating Partnership	51,407				51,407	62,088
Cubesmart, L P and Subsidiaries | Noncontrolling Interests in Operating Partnership
Increase (Decrease) in Partners' Capital
Balance of Noncontrolling Interests in the Operating Partnership	53,845	62,088	60,414	55,819	62,088	55,819
Conversion from OP units to shares	(2,824)		(644)	(1,842)
Adjustment for Operating Partnership interests of third parties	615	(7,976)	2,713	6,681
Net income (loss)	389	383	499	358
Other comprehensive income, net				2
Common OP unit distributions	(618)	(650)	(597)	(604)
Balance of Noncontrolling Interests in the Operating Partnership	51,407	53,845	62,385	60,414	51,407	62,088
Cubesmart, L P and Subsidiaries | Total Shareholders' Equity
Increase (Decrease) in Partners' Capital
Balance	1,782,321	1,799,346	1,697,369	1,709,678	1,799,346	1,709,678
Issuance of common OP units	(70)	(118)
Acquisition of noncontrolling interest in subsidiary			(22,573)	(9,728)
Issuance of common OP units			110,521	24,580
Conversion from OP units to shares	2,824		644	1,842
Exercise of OP unit options	135		962	1,049
Amortization of restricted OP units	1,249	710	1,231	798
OP unit compensation expense	464	530	439	468
Adjustment for Operating Partnership interests of third parties	(615)	7,976	(2,713)	(6,681)
Net income (loss)	38,505	37,896	49,420	35,498
Other comprehensive income, net	20	20	20	240
Common OP unit distributions	(64,081)	(64,039)	(61,431)	(60,375)
Balance	1,760,752	1,782,321	1,773,889	1,697,369	1,760,752	1,799,346
Cubesmart, L P and Subsidiaries | Operating Partner
Increase (Decrease) in Partners' Capital
Balance	$ 1,783,030	$ 1,800,075	$ 1,698,158	$ 1,710,707	$ 1,800,075	$ 1,710,707
Balance (in units)	193,587	193,557	188,137	187,145	193,557	187,145
Issuance of common OP units	$ (70)	$ (118)
Acquisition of noncontrolling interest in subsidiary			$ (22,573)	$ (9,728)
Issuance of common OP units			$ 110,521	$ 24,580
Issuance of common OP units (in units)			3,353	773
Issuance of restricted OP units (in units)	28	30	31	19
Conversion from OP units to shares	$ 2,824		$ 644	$ 1,842
Conversion from OP units to shares (in units)	100		20	60
Exercise of OP unit options	$ 135		$ 962	$ 1,049
Exercise of OP unit options (in units)	14		85	140
Amortization of restricted OP units	$ 1,249	$ 710	$ 1,231	$ 798
OP unit compensation expense	464	530	439	468
Adjustment for Operating Partnership interests of third parties	(615)	7,976	(2,713)	(6,681)
Net income (loss)	38,505	37,896	49,420	35,498
Common OP unit distributions	(64,081)	(64,039)	(61,431)	(60,375)
Balance	$ 1,761,441	$ 1,783,030	$ 1,774,658	$ 1,698,158	$ 1,761,441	$ 1,800,075
Balance (in units)	193,729	193,587	191,626	188,137	193,729	193,557
Cubesmart, L P and Subsidiaries | Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Partners' Capital
Balance	$ (709)	$ (729)	$ (789)	$ (1,029)	$ (729)	$ (1,029)
Other comprehensive income, net	20	20	20	240
Balance	(689)	(709)	(769)	(789)	(689)	(729)
Cubesmart, L P and Subsidiaries | Noncontrolling Interest in Subsidiaries
Increase (Decrease) in Partners' Capital
Balance	7,969	7,990	11,191	6,771	7,990	6,771
Contributions from noncontrolling interests in subsidiaries				4,828
Distributions paid to noncontrolling interests in subsidiaries	(42)	(59)	(8)	(66)
Acquisition of noncontrolling interest in subsidiary			(5,045)	(272)
Net income (loss)	38	38	(41)	(70)
Balance	$ 7,965	$ 7,969	$ 6,097	$ 11,191	$ 7,965	$ 7,990