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Acquisitions (Narrative) (Details) - USD ($) | Mar. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2017 | Feb. 22, 2017 | Oct. 11, 2016
--- | --- | --- | --- | --- | ---
Business Acquisition [Line Items] |  |  |  |  |
Goodwill |  | $ 304,032,000 | $ 320,848,000 |  |
Package Concierge |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Aggregate consideration for acquisition | $ 18,917,000 |  |  |  |
Goodwill |  |  |  | $ 16,931,000 |
Working capital adjustment payable | $ 67,000 |  |  |  |
Nexus Corporation |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Aggregate consideration for acquisition |  | 23,762,000 |  |  |
Goodwill |  |  |  |  | $ 11,451,000
Working capital adjustment payable |  | $ 1,000,000 | $ 167,000 |  |

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