Debt (Lease Narrative) (Details) $ in Thousands		12 Months Ended
	Oct. 06, 2017 USD ($)	Dec. 31, 2017 USD ($) agreement	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)
Capital Leased Assets [Line Items]
Capital lease and lease financing obligations assumed			$ 43,832
Lease financing obligations		$ 900		$ 20,600
Carpathia Hosting, Inc.
Capital Leased Assets [Line Items]
Capital lease, lease financing obligations and mortgage notes payable		7,800
Capital lease and lease financing obligations assumed		$ 5,700
Number of lease agreements | agreement		2
Outstanding financing agreement		$ 900
Carpathia Hosting, Inc. | Tenant Improvement Allowance [Member]
Capital Leased Assets [Line Items]
Lease financing obligations		$ 4,800
Lease financing expiration date		Feb. 28, 2019
Vault Campus in Dulles, Virginia
Capital Leased Assets [Line Items]
Capital lease and lease financing obligations assumed	$ 17,800
Purchase price of land	34,100
Net purchase price	$ 16,300
Minimum | Carpathia Hosting, Inc.
Capital Leased Assets [Line Items]
Lease expiration year		2018
Monthly lease payment		$ 200
Maximum | Carpathia Hosting, Inc.
Capital Leased Assets [Line Items]
Lease expiration year		2019
Monthly lease payment		$ 500
Maximum | Carpathia Hosting, Inc. | Tenant Improvement Allowance [Member]
Capital Leased Assets [Line Items]
Lease financing monthly principal and interest payment		$ 100