Operating Leases - Right-of-use asset and operating lease liability (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use asset	$ 32,180	$ 19,894
Operating lease liability	$ 33,968	$ 22,039
Right-of-use asset, balance sheet	us-gaap:OtherAssets	us-gaap:OtherAssets
Operating lease liability, balance sheet	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities