Leases - Schedule of the components of lease expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Amortization of right-of-use asset	$ 152	$ 124	$ 304	$ 282
Interest on lease liabilities	9	10	19	19
Total finance lease cost	161	134	323	301
Operating lease cost	5,669	$ 5,223	11,149	$ 10,007
Subsidiaries
Related Party Transaction [Line Items]
Right-of-Use, Modification, Operating					$ 14,700
Land | Subsidiaries
Related Party Transaction [Line Items]
Operating lease cost	$ 200		$ 500