Acquisitions - Manatee Works Inc. Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Aug. 21, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Revaluation of contingent consideration		$ (463)	$ (790)	$ 0
Payment of contingent consideration		337	0	$ 0
Manatee Works, Inc. [Member]
Business Acquisition [Line Items]
Purchase price	$ 4,813
Cash paid in purchase price	1,023
Contingent consideration liability	$ 3,790	2,200	3,000
Revaluation of contingent consideration		463	$ 790
Payment of contingent consideration		337
Contingent consideration, current		800
Contingent consideration, noncurrent		$ 1,400
Intangible assets, useful life	5 years
Scenario, Forecast [Member] | Manatee Works, Inc. [Member]
Business Acquisition [Line Items]
Contingent consideration, low range					$ 0	$ 0
Contingent consideration, high range					$ 2,200	$ 1,700