Leases (Summary of Lease Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating lease assets	$ 146,522	$ 170,056
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Finance lease assets	$ 13,179	$ 15,713
Total lease assets	$ 159,701	$ 185,769
Liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	amcx:OperatingAndFinanceLeaseLiabilityCurrent	amcx:OperatingAndFinanceLeaseLiabilityCurrent
Current operating lease liabilities	$ 28,813	$ 30,171
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	amcx:OperatingAndFinanceLeaseLiabilityCurrent	amcx:OperatingAndFinanceLeaseLiabilityCurrent
Current finance lease liabilities	$ 3,622	$ 3,788
Total current lease liabilities	$ 32,435	$ 33,959
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	amcx:OperatingAndFinanceLeaseLiabilityNoncurrent	amcx:OperatingAndFinanceLeaseLiabilityNoncurrent
Noncurrent operating lease liabilities	$ 166,452	$ 193,570
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	amcx:OperatingAndFinanceLeaseLiabilityNoncurrent	amcx:OperatingAndFinanceLeaseLiabilityNoncurrent
Noncurrent finance lease liabilities	$ 27,872	$ 17,477
Total noncurrent lease liabilities	194,324	211,047
Total lease liabilities	$ 226,759	$ 245,006