For investments which are quantified by principal amount, the principle balance held at close of period.

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Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Unfunded commitments	$ 4		$ 4		$ 2
Deposits from related parties	238,891		238,891		110,465
Aviation Time Sharing Agreement
Related Party Transaction [Line Items]
Payments to related party	53	$ 2	125	$ 27
Registration Rights Agreement \| 2016 IPO
Related Party Transaction [Line Items]
Payments to related party	700
Certain Executive Officers and Directors and Their Associates
Related Party Transaction [Line Items]
Unfunded commitments	10,189		10,189		4,672
Shareholders
Related Party Transaction [Line Items]
Unamortized leasehold improvements	126		126		137
Lease expense	111	$ 124	259	$ 250
Director \| Other Assets
Related Party Transaction [Line Items]
Amount of investment held by the company	$ 127		$ 127		$ 200