Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Accounting Policies [Abstract]
Unsatisfied performance obligation	$ 90,500		$ 90,500
Amount of remaining performance obligation	80.00%		80.00%
Allowance for doubtful accounts	$ 3,200		$ 3,200		$ 4,400
Unearned revenue	6,522		6,522		$ 11,459
Prior year unearned revenue recognized in period			7,000
Share-based compensation costs	$ 2,800	$ 2,900	$ 8,600	$ 6,300
Antidilutive securities excluded from computation of Earnings Per Share, amount			1.4

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Total carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue or other forms of income in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer.

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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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Percentage of remaining performance obligation to total remaining performance obligation not recognized as revenue.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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