Leases - Components of Net Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Finance leases:
Amortization of right-of-use assets	$ 388	$ 449	$ 1,159	$ 1,427
Interest on lease liabilities	54	62	167	194
Operating lease cost	1,332	1,306	3,979	3,885
Short-term lease cost	108	104	337	324
Variable lease cost	310	304	928	983
Sublease income	(118)	(84)	(271)	(246)
Net lease cost	$ 2,074	$ 2,141	$ 6,299	$ 6,567

Finance lease.

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- Definition

Amount of interest expense on finance lease liability.

+ References

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- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

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- Definition

Amount of lease cost recognized by lessee for lease contract.

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- Definition

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.

+ References

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- Definition

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

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- Definition

Amount of sublease income excluding finance and operating lease expense.

+ References

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- Definition

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

+ References

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