Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Thousands						1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 15, 2020 $ / shares	May 09, 2019 shares	Mar. 15, 2018	May 04, 2015 shares	Oct. 13, 2013 Vote shares	Mar. 31, 2019	Mar. 31, 2020 USD ($) class shares	Mar. 31, 2019 USD ($)	Dec. 31, 2019 shares
Partners Capital And Distributions [Line Items]
Options outstanding							200,000
Equity based compensation expense unrecognized | $							$ 40,200
Equity based compensation expense vesting period							1 year 1 month 6 days
Preferred Stock, Dividend Rate, Percentage			7.125%
Proceeds net of fees from common equity offering | $								$ 158,663
Class B Common Stock
Partners Capital And Distributions [Line Items]
Number of votes per share | Vote					50
Series A Redeemable Perpetual Preferred Stock
Partners Capital And Distributions [Line Items]
Preferred Stock, Dividend Rate, Percentage							7.125%		7.125%
Series A Redeemable Perpetual Preferred Stock | Subsequent Event
Partners Capital And Distributions [Line Items]
Dividend paid to common stockholders | $ / shares	$ 0.45
Chief Executive Officer | Class B Common Stock
Partners Capital And Distributions [Line Items]
Percentage of operating partnership unit exchanged					2.00%
Class O Units and Options
Partners Capital And Distributions [Line Items]
Equity based compensation awards intrinsic value | $							$ 42,300
Restricted Class A Common Stock
Partners Capital And Distributions [Line Items]
Vesting period							2 years
Performance-Based FFO Units | Minimum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award						0.00%
Performance-Based FFO Units | Maximum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award						200.00%
Performance-Based Relative TSR Units
Partners Capital And Distributions [Line Items]
Vesting period						3 years
Performance-Based Relative TSR Units | Minimum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award						0.00%
Performance-Based Relative TSR Units | Maximum | Class A Common Stock
Partners Capital And Distributions [Line Items]
Percentage of target award						200.00%
Options to purchase Class A common stock
Partners Capital And Distributions [Line Items]
Equity based compensation awards intrinsic value | $							$ 42,300
2013 Equity Incentive Plan | Class A Common Stock
Partners Capital And Distributions [Line Items]
Authorized shares to be issued under the plan					1,750,000
Additional shares available for issuance under plan approved by stockholders		1,110,000		3,000,000
Shares available for issuance		5,860,000
2013 Equity Incentive Plan | Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Options outstanding									84,202
2013 Equity Incentive Plan | Performance-Based Relative TSR Units
Partners Capital And Distributions [Line Items]
Options outstanding									84,202
Qualitytech, LP
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding | class							4
Proceeds net of fees from common equity offering | $								$ 158,663
Qualitytech, LP | Preferred Units Series A [Member]
Partners Capital And Distributions [Line Items]
Exchange rate for cash or shares							1
First portion | Restricted Class A Common Stock
Partners Capital And Distributions [Line Items]
Vesting period							1 year
Vesting percentage							33.00%
First portion | Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Vesting period						2 years
Vesting percentage						67.00%
Second portion | Restricted Class A Common Stock
Partners Capital And Distributions [Line Items]
Vesting percentage, per quarter							8.375%
Second portion | Performance-Based FFO Units
Partners Capital And Distributions [Line Items]
Vesting period						3 years
Vesting percentage						33.00%