Acquisitions - Additional Information (Detail) £ / shares in Units, € in Millions, £ in Millions							3 Months Ended			5 Months Ended	9 Months Ended		12 Months Ended
	May 01, 2017 USD ($) data_center_building	Feb. 03, 2017 USD ($)	Aug. 01, 2016 EUR (€)	Aug. 01, 2016 USD ($)	Jan. 15, 2016 GBP (£) £ / shares	Jan. 15, 2016 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 06, 2016 USD ($)	May 29, 2015 GBP (£)	May 29, 2015 USD ($)
Business Acquisition [Line Items]
Revenues							$ 1,152,261,000		$ 924,676,000		$ 3,168,207,000	$ 2,669,342,000
Net income							79,900,000		51,450,000		167,767,000	65,050,000
Goodwill							4,226,490,000	$ 2,986,064,000		$ 4,226,490,000	4,226,490,000		$ 2,986,064,000
Repayment of capital lease and other financing obligations											60,252,000	100,863,000
Loss on debt extinguishment							22,156,000		9,894,000		42,103,000	10,499,000
Verizon [Member]
Business Acquisition [Line Items]
Data center buildings | data_center_building	29
Cash consideration for acquisition	$ 3,600,000,000
Acquisition costs							1,200,000				27,600,000
Revenues							137,000,000			223,700,000	223,700,000
Net income							$ 29,200,000			$ 56,300,000
Property, plant and equipment	841,401,000
Goodwill	1,083,789,000
Intangible assets	1,706,100,000
Capital lease and other financing obligations	17,659,000
Deferred tax liabilities	$ 19,544,000
IO [Member]
Business Acquisition [Line Items]
Cash consideration for acquisition		$ 36,300,000
Revenues											4,000,000
Property, plant and equipment		40,300,000
Goodwill		16,200,000
Intangible assets		6,300,000
Deferred tax assets		6,300,000
Capital lease and other financing obligations		$ 33,100,000
Acquired intangible assets, Estimated useful lives (years)		10 years
Digital Realty [Member]
Business Acquisition [Line Items]
Cash consideration for acquisition			€ 193.8	$ 216,400,000
Acquisition costs													12,000,000
Revenues											9,100,000
Property, plant and equipment				143,972,000
Goodwill				48,835,000
Intangible assets				11,758,000
Repayment of capital lease and other financing obligations			47.8	53,400,000
Loss on debt extinguishment			€ 8.8	9,900,000
Deferred tax liabilities				$ 42,395,000
Telecity Group plc [Member]
Business Acquisition [Line Items]
Acquisition costs													42,500,000
Revenues									107,300,000			299,000,000
Net income									$ 15,700,000			$ 54,400,000
Property, plant and equipment						$ 1,058,583,000
Goodwill						2,215,567,000
Intangible assets						694,243,000
Deferred tax assets						994,000
Capital lease and other financing obligations						$ 165,365,000
Payments to acquire businesses, per share acquired | £ / shares					£ 5.725
Ratio of shares acquired					0.0336	0.0336
Consideration transferred					£ 2,624.5	$ 3,743,600,000
Assumed, unvested stock compensation awards						1,300,000
Cash placed in restricted account															£ 322.9	$ 475,700,000
Business combination, provisional information, initial accounting incomplete, adjustment, intangibles								36,800,000
Business combination, provisional information, initial accounting incomplete, adjustment, deferred tax liabilities								19,500,000
Business combination, provisional information, initial accounting incomplete, adjustment, capital lease and other financing obligations								(34,400,000)
Business combination, provisional information, initial accounting incomplete, adjustment, goodwill								(22,500,000)
Business combination, provisional information, initial accounting incomplete, adjustment, asets held for sale								$ (36,900,000)
Deferred tax liabilities						$ 176,168,000
Telecity Group plc [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Discount rate (percent)					8.50%	8.50%
Acquired intangible assets, Estimated useful lives (years)					13 years 6 months	13 years 6 months
Telecity Group plc [Member] | Trade names [Member]
Business Acquisition [Line Items]
Discount rate (percent)					9.00%	9.00%
Acquired intangible assets, Estimated useful lives (years)					1 year 6 months	1 year 6 months
Relief of royalty rate (percent)					2.00%	2.00%
Bridge term loan [Member] | Verizon [Member]
Business Acquisition [Line Items]
Short-term debt														$ 2,000,000,000.0
Payments of financing costs											10,000,000
Commitment fees											$ 7,800,000		$ 2,200,000
Minimum [Member] | Verizon [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Discount rate (percent)	7.70%
Maximum [Member] | Verizon [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Discount rate (percent)	14.40%