Derivative Instruments (Outstanding Interest Rate Derivatives) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($) $ / £ $ / $	Dec. 31, 2017 USD ($) $ / £ $ / $
Digital Realty Trust, L.P. | Unsecured term loan — 5-year
Currently-paying contracts
Debt instrument term	5 years
Digital Realty Trust, L.P. | Unsecured term loan — 7-year
Currently-paying contracts
Debt instrument term	7 years
Digital Realty Trust, L.P. | Unsecured Term Loans | British pound sterling (£)
Currently-paying contracts
Exchange rate | $ / £	1.30	1.35
Digital Realty Trust, L.P. | Unsecured Term Loans | Canadian dollar (CAD)
Currently-paying contracts
Exchange rate | $ / $	0.77	0.80
Interest Rate Swap, 1.611
Currently-paying contracts
Notional Amount	$ 206,000	$ 206,000
Strike Rate	1.611%
Interest Rate Swap, 1.611 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 2,856	1,409
Interest Rate Swap, 1.605
Currently-paying contracts
Notional Amount	$ 54,905	54,905
Strike Rate	1.605%
Interest Rate Swap, 1.605 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 747	374
Interest Rate Swap 1.016
Currently-paying contracts
Notional Amount	$ 75,000	75,000
Strike Rate	1.016%
Interest Rate Swap 1.016 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 3,023	2,260
Interest Rate Swap, 1.164
Currently-paying contracts
Notional Amount	$ 75,000	75,000
Strike Rate	1.164%
Interest Rate Swap, 1.164 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 2,808	1,947
Interest Rate Swap, 1.435
Currently-paying contracts
Notional Amount	$ 300,000	300,000
Strike Rate	1.435%
Interest Rate Swap, 1.435 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 17,829	9,978
Interest Rate Swap, 0.792
Currently-paying contracts
Notional Amount	$ 220,843	229,012
Strike Rate	0.792%
Interest Rate Swap, 0.792 | Level 2
Currently-paying contracts
Fair value of derivatives	$ (24)	(430)
Interest Rate Swap, 0.779
Currently-paying contracts
Notional Amount	$ 76,298	78,357
Strike Rate	0.779%
Interest Rate Swap, 0.779 | Level 2
Currently-paying contracts
Fair value of derivatives	$ 2,960	3,034
Interest Rate Swap
Currently-paying contracts
Notional Amount	1,008,046	1,018,274
Interest Rate Swap | Level 2
Currently-paying contracts
Fair value of derivatives	$ 30,199	$ 18,572