Noncontrolling Interest Represented By Preferred Operating Partnership Units - Additional Information (Details) $ / shares in Units, $ in Thousands											1 Months Ended	6 Months Ended	12 Months Ended
	Nov. 04, 2016 USD ($) shares	May 31, 2016 USD ($)	May 21, 2016 USD ($) store shares	Oct. 03, 2014 USD ($) shares	Apr. 03, 2014 USD ($) store shares	Nov. 19, 2013 store	Sep. 26, 2013 USD ($) shares	Aug. 29, 2013 store	Jun. 25, 2007 USD ($) shares	Jun. 15, 2007 store shares	Dec. 31, 2014 USD ($) shares	May 31, 2014 USD ($) store shares	Dec. 31, 2016 USD ($) shares property $ / shares	Dec. 31, 2015 USD ($) property shares	Jun. 15, 2016 USD ($)
Noncontrolling Interest [Line Items]
Loan to holders of preferred OP units													$ 120,230	$ 120,230
Number of stores | property													99	171
Number of OP Units Issued | shares													2,779,050	2,043,613,000
Value of OP Units Issued													$ 74,235	$ 142,399
Loan Assumed													$ 9,723	$ 0
Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Value of OP Units Issued		$ 205
Series A Participating Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Number of stores acquired | store										10
Series A Participating Redeemable Preferred Units [Member] | Holders Of Series A Preferred Operating Partnership Units [Member]
Noncontrolling Interest [Line Items]
Loan to holders of preferred OP units									$ 100,000
Note receivable interest rate (as a percent)									4.85%
Maximum number of preferred OP units converted prior to the maturity date of the loan (in shares) | shares									114,500
A units redeemed | shares				114,500
A units redeemed ,value				$ 4,794
Common shares issued in Preferred Unit redemption | shares				280,331
Additional units redeemed | shares				0
Series A Units [Member] | Series A Participating Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Preferred units issued as part of acquisition (in units) | shares										989,980
Fixed priority return on preferred OP units, amount															$ 115,000
Fixed priority return on preferred OP units, stated return rate (as a percent)													5.00%
Fixed priority return on preferred OP units, liquidation value													$ 115,000
Series B Units [Member] | Series B Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Liquidation value (in dollars per share) | $ / shares													$ 25
Fixed liquidation value													$ 41,903
Annual rate of return (as a percent)													6.00%
Series C Units [Member] | Series C Convertible Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Loan to holders of preferred OP units											$ 20,230
Note receivable interest rate (as a percent)											5.00%
Liquidation value (in dollars per share) | $ / shares													$ 42.10
Fixed liquidation value													$ 29,639
Quarterly distribution per preferred OP unit payable above quarterly distribution for common OP Unit | $ / shares													$ 0.18
Basis for determining fixed quarterly distribution in year 5, period before fifth anniversary													12 months
Period from date of issuance after which preferred OP units will become redeemable at the option of the holder													1 year
Period from date of issuance after which preferred OP units will become convertible into common OP units at the option of the holder													1 year
Preferred OP units conversion ratio | shares													0.9145
Series D Units [Member] | Series D Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Liquidation value (in dollars per share) | $ / shares													$ 25.00
Fixed liquidation value													$ 80,903
Georgia, 1 Property Acquired 4/3/2014 [Member] | Series B Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Number of stores acquired | store					1
Cash portion of payment for acquisition					$ 15,158
Georgia, 1 Property Acquired 4/3/2014 [Member] | Series B Units [Member] | Series B Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Preferred units issued as part of acquisition (in units) | shares					333,360
Preferred units issued as part of acquisition					$ 8,334
California Properties Sep 2013 [Member] | Series B Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Number of stores acquired | store								19
Cash portion of payment for acquisition							$ 100,876
Number of stores acquired as part of portfolio acquisition | store								20
Loan Assumed							$ 98,960
Number of common units issued as part of acquisition | shares							1,448,108
OP units issued as part of the acquisition							$ 62,341
California Properties Sep 2013 [Member] | Series B Units [Member] | Series B Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Preferred units issued as part of acquisition (in units) | shares							1,342,727
Preferred units issued as part of acquisition							$ 33,568
California Properties Dec 2013 and May 2014 [Member] | Series C Convertible Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Number of stores acquired | store						12
Ownership interest in five stores through joint ventures prior to the acquisition												35.00%
Number of stores in which ownership interest was held prior to acquisition of remaining properties | store												5
Ownership interest in one store through joint ventures prior to the acquisition												40.00%
Number of stores in which ownership interest was held prior to acquisition | store												1
California Properties Dec 2013 and May 2014 [Member] | Series C Convertible Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Cash portion of payment for acquisition												$ 45,722
Loan Assumed												$ 37,532
Number of stores acquired | store												6
California Properties Dec 2013 and May 2014 [Member] | Series C Units [Member] | Series C Convertible Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Preferred units issued as part of acquisition (in units) | shares												704,016
Preferred units issued as part of acquisition												$ 30,960
Self Storage Facility [Member] | Series D Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Cash portion of payment for acquisition											$ 5,621
Self Storage Facility [Member] | Series D Units [Member] | Series D Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Preferred units issued as part of acquisition (in units) | shares											548,390
Preferred units issued as part of acquisition											$ 13,710
Illinois Properties Jun 10, 2016 [Member]
Noncontrolling Interest [Line Items]
Number of stores | store			4
Number of OP Units Issued | shares													2,201,467
Value of OP Units Issued													$ 55,037
Loan Assumed													$ 0
Illinois Properties May and Nov 2016 [Member] | Series D-3 Preferred Units [Member] | Series D Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Number of OP Units Issued | shares			2,201,467
Value of OP Units Issued			$ 55,037
Illinois Properties May and Nov 2016 [Member] | Series D-4 Preferred Units [Member] | Series D Redeemable Preferred Units [Member] | Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Number of OP Units Issued | shares	486,244,000
Value of OP Units Issued	$ 12,156
Minimum [Member] | Series D-1 Preferred Units [Member] | Series D Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Annual rate of return (as a percent)													3.50%
Maximum [Member] | Series D-1 Preferred Units [Member] | Series D Redeemable Preferred Units [Member]
Noncontrolling Interest [Line Items]
Annual rate of return (as a percent)													5.00%