Acquisition of eSignLive - Summary of Unaudited Pro Forma Amounts (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unaudited Pro Forma Financial Information
Statutory tax rate	35.00%	34.00%	34.00%
Estimated amortization of acquired identifiable intangible assets	$ 8,809	$ 8,849	$ 4,942
eSignLive
Unaudited Pro Forma Financial Information
Revenue			256,416
Net income			$ 22,247
Pro Forma \| eSignLive
Unaudited Pro Forma Financial Information
Statutory tax rate			35.00%
Estimated amortization of acquired identifiable intangible assets			$ 6,060
Estimated amortization of fair value adjustment of acquired deferred revenue			(4,000)
Reverse benefit of refundable tax credits			$ (1,021)

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.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Fair value adjustment estimated amortization of acquired deferred revenue.

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