Lease Commitments - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease assets, net	$ 91,884	$ 80,752
Finance lease assets	$ 4,669	$ 4,577
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentGross	us-gaap:PropertyPlantAndEquipmentGross
Total leased assets	$ 96,553	$ 85,329
Operating lease, liability, current	$ 23,338	$ 27,663
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Finance lease, liability, current	$ 778	$ 265
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	ctb:LongTermDebtCurrentExcludingNotesPayableCurrent	ctb:LongTermDebtCurrentExcludingNotesPayableCurrent
Operating lease, liability, noncurrent	$ 71,391	$ 55,371
Finance lease, liability, noncurrent	$ 1,332	$ 935
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations
Total lease liabilities	$ 96,839	$ 84,234