Catalyzes the hydrolysis of acyl-CoAs into free fatty acids and coenzyme A (CoASH), regulating their respective intracellular levels. More active towards saturated and unsaturated long chain fatty acyl-CoAs (C12-C20). . This is the function of ACOT1 (acyl-CoA thioesterase 1, Ensembl gene identifier ENSG00000184227).