Intangible Assets, Net - Net Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Severance	$ 1,446	$ 2,701	$ 1,495
Impairment of intangible assets	0	0	$ 0
Gross Carrying Amount	39,208	41,578
Accumulated Amortization	(28,405)	(26,614)
Net Balance	$ 10,803	14,964
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002	25,002
Accumulated Amortization	(14,585)	(12,084)
Net Balance	10,417	12,918
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,452	8,452
Accumulated Amortization	(8,452)	(8,339)
Net Balance	$ 0	113
Acquired technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Acquired technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	4 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	3 years
Gross Carrying Amount	$ 0	2,370
Accumulated Amortization	0	(2,352)
Net Balance	$ 0	18
Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	6 years
Gross Carrying Amount	$ 5,754	5,754
Accumulated Amortization	(5,368)	(3,839)
Net Balance	$ 386	$ 1,915
Software
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	3 years	15 years
Amortization period at reassessment		3 years
Former Executive | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	3 years
Amcom Software, Inc | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Amcom Software, Inc | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years