Intangible Assets, Net - Summary (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets
Gross Value	$ 36,557	$ 20,863
Accumulated Amortization	(11,682)	(5,598)
Net Carrying Value	$ 24,875	$ 15,265
Weighted Average Remaining Useful Life	6 years 6 months	5 years 10 months 24 days
Amortization expense for intangible assets	$ 6,100	$ 3,700	$ 2,000
Client relationships
Intangible assets
Gross Value	22,581	11,651
Accumulated Amortization	(6,226)	(3,219)
Net Carrying Value	$ 16,355	$ 8,432
Weighted Average Remaining Useful Life	8 years 6 months	7 years 10 months 24 days
Client relationships \| Minimum
Intangible assets
Useful life	2 years	2 years
Client relationships \| Maximum
Intangible assets
Useful life	10 years	10 years
Non-compete agreements
Intangible assets
Gross Value	$ 3,480	$ 3,410
Accumulated Amortization	(2,344)	(1,360)
Net Carrying Value	$ 1,136	$ 2,050
Weighted Average Remaining Useful Life	1 year 7 months 6 days	2 years 3 months 18 days
Non-compete agreements \| Minimum
Intangible assets
Useful life	1 year 6 months	3 years
Non-compete agreements \| Maximum
Intangible assets
Useful life	5 years	5 years
Trademarks
Intangible assets
Gross Value	$ 1,320	$ 140
Accumulated Amortization	(287)	(44)
Net Carrying Value	$ 1,033	$ 96
Useful life	3 years	3 years
Weighted Average Remaining Useful Life	2 years 4 months 24 days	2 years 1 month 6 days
Patents
Intangible assets
Gross Value	$ 200
Accumulated Amortization	(6)
Net Carrying Value	$ 194
Useful life	3 years	3 years
Weighted Average Remaining Useful Life	2 years 10 months 24 days
Internal-Use Software
Intangible assets
Gross Value	$ 8,976	$ 5,662
Accumulated Amortization	(2,819)	(975)
Net Carrying Value	$ 6,157	$ 4,687
Weighted Average Remaining Useful Life	3 years	3 years 9 months 18 days
Internal-Use Software \| Minimum
Intangible assets
Useful life	3 years	3 years
Internal-Use Software \| Maximum
Intangible assets
Useful life	5 years	5 years

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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