General - Leases - Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Components of lease assets and liabilities
Operating lease right-of-use assets	$ 17,453
Operating Lease, Right-of-Use Asset, Statement of Financial Position	us-gaap:OtherAssetsNoncurrent
Current operating lease liabilities	$ 9,762
Operating Lease, Liability, Current, Statement of Financial Position	us-gaap:AccruedLiabilitiesCurrent
Long-term operating lease liabilities	$ 23,990
Operating Lease, Liability, Noncurrent, Statement of Financial Position	us-gaap:DeferredCreditsAndOtherLiabilitiesNoncurrent
Total operating lease liabilities	$ 33,752
Operating Lease, Liability, Statement of Financial Position	us-gaap:AccruedLiabilitiesCurrent us-gaap:DeferredCreditsAndOtherLiabilitiesNoncurrent
Finance lease assets	$ 13,100
Finance Lease, Right-of-Use Asset, Statement of Financial Position	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Current finance lease liabilities	$ 4,416
Finance Lease, Liability, Current, Statement of Financial Position	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Long-term finance lease liabilities	$ 13,186
Finance Lease, Liability, Noncurrent, Statement of Financial Position	us-gaap:LongTermDebtAndCapitalLeaseObligations
Total finance lease liabilities	$ 17,602	$ 18,100
Total lease liabilities	$ 51,354