Operating Leases (Lease Cost, Term and Discount Rate) (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Lease Cost
Net lease cost	$ 1,985	$ 4,533
Operating leases, weighted-average remaining term	2 years 8 months 12 days	2 years 8 months 12 days
Operating leases, weighted-average discount rate	5.00%	5.00%
Selling, general and administrative expenses
Lease Cost
Operating lease cost	$ 1,469	$ 3,147
Short-term lease cost	528	1,354
Variable lease cost	172	396
Other income, net
Lease Cost
Sublease income	$ (184)	$ (364)

Amount of lease cost recognized by lessee for lease contract.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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Amount of sublease income excluding finance and operating lease expense.

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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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