Acquisitions - Secure-i Acquisition (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Dec. 08, 2014	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Cash not yet paid for business acquisitions			$ 417	$ 434	$ 0
Other current liabilities			2,219	2,143
Goodwill			24,723	$ 21,374	$ 18,480
Secure-i
Business Acquisition [Line Items]
Cash paid to acquire business	$ 2,610		145
Cash not yet paid for business acquisitions	290
Other current liabilities			$ 145
Intangible assets acquired	700
Goodwill	2,202
Increase in goodwill due to working capital adjustment		$ 20
Secure-i | Customer Relationships
Business Acquisition [Line Items]
Intangible assets acquired	$ 208
Weighted-average estimated useful life of intangible assets acquired	12 years
Secure-i | Developed Technology
Business Acquisition [Line Items]
Intangible assets acquired	$ 228
Weighted-average estimated useful life of intangible assets acquired	3 years
Secure-i | Income Approach Valuation Technique | Customer Relationships
Business Acquisition [Line Items]
Customer retention rate	90.00%
Discount rate	20.00%
Secure-i | Cost Approach Valuation Technique | Developed Technology
Business Acquisition [Line Items]
Fair Value Inputs, Inflation And Obsolescence Adjustment, Percentage	20.00%
Adjustment for developer's profit rate	35.00%