Nature of Business and Summary of Significant Accounting Policies - Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, Cost	$ 15,700	$ 15,700
Finite-lived intangible assets, Accumulated amortization	(8,312)	(8,155)
Finite-lived intangible assets, Net book value	7,388	7,545
Customer Relationships [Member]
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, Cost	9,800	9,800
Finite-lived intangible assets, Accumulated amortization	(8,312)	(8,155)
Finite-lived intangible assets, Net book value	1,488	1,645
Trade name [Member]
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, Cost	5,900	5,900
Finite-lived intangible assets, Accumulated amortization	0	0
Finite-lived intangible assets, Net book value	$ 5,900	$ 5,900