Other Operating Expenses - Summary of Major Components of Other Operating Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2017
Other Operating Expenses [Abstract]
Directors' fees	$ 89	$ 114	$ 129
Miscellaneous taxes	120	69	87
Computer expenses	74	65	125
Depreciation and amortization	23	24	49
Other expenses	281	215	406
Total other operating expenses	$ 587	$ 487	$ 796