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
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Deposits from related parties	$ 272,744		$ 238,781
Aviation Time Sharing Agreement
Related Party Transaction [Line Items]
Payments to related party	33	$ 27
Certain Executive Officers, Certain Management and Directors and Their Associates
Related Party Transaction [Line Items]
Unfunded commitments	21,518		19,404
Director
Related Party Transaction [Line Items]
Unamortized leasehold improvements	76		$ 86
Lease expense	$ 128	$ 129