Noncontrolling Interests - Operating Partnership (Details) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2017 shares
Noncontrolling Interests - Operating Partnership
Closing price of the Company's stock (in dollars per share) \| $ / shares	$ 111.14
Noncontrolling Interests
Noncontrolling Interests - Operating Partnership
Reduction to noncontrolling interests in the Operating Partnership and an increase to common stock and additional paid in capital \| $	$ 20,967
Noncontrolling Interests \| Carlyle Group
Noncontrolling Interests - Operating Partnership
Common Operating Partnership units redeemed for common stock (in shares)	2,257,056
Reduction to noncontrolling interests in the Operating Partnership and an increase to common stock and additional paid in capital \| $	$ 21,000
Operating partnership
Noncontrolling Interests - Operating Partnership
Conversion ratio for common operating partnership units	1
Number of Operating Partnership Units (in shares)	47,824,565	47,662,600
Percentage of Total	100.00%	100.00%
Shares of common stock issued related to employee compensation arrangements	169,021
Quarterly distributions will receive by holders of operating partnership units (in dollars per unit) \| $ / shares	$ 3.04
Operating partnership \| Carlyle Group
Noncontrolling Interests - Operating Partnership
Percentage of Total	24.20%
Operating partnership \| Coresite Realty Corporation
Noncontrolling Interests - Operating Partnership
Number of Operating Partnership Units (in shares)	36,245,285	33,826,264
Percentage of Total	75.80%	71.00%
Operating partnership \| Noncontrolling Interests
Noncontrolling Interests - Operating Partnership
Number of Operating Partnership Units (in shares)	11,579,280	13,836,336
Percentage of Total	24.20%	29.00%
Redemption value of the noncontrolling interests \| $	$ 1,300,000

Represents the ownership percentage expressed as a percentage.

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Represents the ratio for conversion of Operating Partnership units held by noncontrolling interests into common stock at the option of the entity.

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Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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The number of units redeemed during the year of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

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The aggregate fair value as of the reporting date of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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Price of a single share of a number of saleable stocks of a company.

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Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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