Migrat completed docs from EchoSign to Document Cloud

Hello,

We recently created a 'new' Adobe sign/document cloud account VS 'upgrading' our old 'echosign' account for internal reasons. My question is now, how do we take all our historical documents from our old account and Migrate them to our new DocumentCloud account? Is there a bulk download or service we can use to complete this task?

Any help would be greatly appreciated. 

Thank you,