Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Entity Registrant Name	QTS Realty Trust, Inc.
Entity Central Index Key	0001577368
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Small Business	false
Entity Emerging Growth Company	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		51,007,775
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		128,408
Qualitytech, LP
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Entity Registrant Name	QualityTech, LP
Entity Central Index Key	0001561164
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Small Business	false
Entity Emerging Growth Company	false