Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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Related party transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Deposits from related parties	$ 277,904		$ 277,904		$ 238,781
Aviation Time Sharing Agreement
Related Party Transaction [Line Items]
Payments to related party	58	$ 70	91	$ 97
Certain Executive Officers, Certain Management and Directors and Their Associates
Related Party Transaction [Line Items]
Unfunded commitments	20,302		20,302		19,404
Director
Related Party Transaction [Line Items]
Unamortized leasehold improvements	68		68		$ 86
Lease expense	$ 128	$ 124	$ 256	$ 253