Other Operating Expenses - Summary of Major Components of Other Operating Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Other Operating Expenses [Abstract]
Directors’ fees	$ 89	$ 319
Miscellaneous taxes	120	258
Computer expense	74	244
Other expenses	304	727
Total other operating expenses	$ 587	$ 1,548