Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands		9 Months Ended
	Jan. 01, 2019	Sep. 30, 2019
Accounting Policies [Line Items]
Net lease assets		$ 6,459
Lease liabilities		6,963
Adjustment to retained earnings		$ 93
ASC 842 [Member]
Accounting Policies [Line Items]
Net lease assets	$ 3,100
Lease liabilities	3,100
Adjustment to retained earnings	$ 100