National Storage Affiliates Trust Quarterly report pursuant to Section 13 or 15(d)

DEBT FINANCING - Debt Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt, principal amount	$ 1,414,360	$ 1,277,638
Unamortized debt issuance costs and debt premium, net	566	464
Total debt	$ 1,414,926	1,278,102
Line of Credit \| Credit Facility \| Revolving line of credit
Debt Instrument [Line Items]
Effective interest rate (percent)	3.89%
Debt, principal amount	$ 277,500	139,500
Unsecured Debt \| Credit Facility \| Term loan A
Debt Instrument [Line Items]
Effective interest rate (percent)	2.91%
Debt, principal amount	$ 235,000	235,000
Unsecured Debt \| Credit Facility \| Term loan B
Debt Instrument [Line Items]
Effective interest rate (percent)	2.94%
Debt, principal amount	$ 155,000	155,000
Unsecured Debt \| Credit Facility \| Term loan C
Debt Instrument [Line Items]
Effective interest rate (percent)	3.71%
Debt, principal amount	$ 105,000	105,000
Unsecured Debt \| Credit Facility \| Term loan D
Debt Instrument [Line Items]
Effective interest rate (percent)	3.79%
Debt, principal amount	$ 125,000	125,000
Unsecured Debt \| 2023 Term loan facility
Debt Instrument [Line Items]
Effective interest rate (percent)	3.13%
Debt, principal amount	$ 175,000	175,000
Unsecured Debt \| 2028 Term loan facility
Debt Instrument [Line Items]
Effective interest rate (percent)	4.62%
Debt, principal amount	$ 75,000	75,000
Mortgages \| Fixed rate mortgages payable
Debt Instrument [Line Items]
Effective interest rate (percent)	4.18%
Debt, principal amount	$ 266,860	$ 268,138