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Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	Aug. 21, 2018	Feb. 22, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Oct. 11, 2016
Business Acquisition [Line Items]
Goodwill			$ 304,032	$ 323,671	$ 321,074
SolarBOS
Business Acquisition [Line Items]
Acquisition purchase price	$ 6,500
Goodwill	3,051
Fair value of purchase consideration	$ 6,541
Package Concierge
Business Acquisition [Line Items]
Acquisition purchase price		$ 18,900
Goodwill		16,790
Fair value of purchase consideration		$ 18,917
Nexus
Business Acquisition [Line Items]
Acquisition purchase price			$ 23,800
Goodwill						$ 11,451
Fair value of purchase consideration						$ 23,762

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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