Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating losses	$ 79	$ 123
Residential product warranty reserve	7,804	8,876
Stock-based compensation	1,725	1,823
Accruals not currently deductible and other	3,928	1,838
Inventories	4,682	3,783
State tax credit carryforwards	3,400	3,619
Gross deferred tax assets, before valuation allowance	21,618	20,062
Valuation allowance	(3,015)	(3,096)
Gross deferred tax assets, after valuation allowance	18,603	16,966
Deferred tax liabilities:
Depreciation	(13,893)	(12,046)
Goodwill amortization	(3,774)	(2,781)
Inventories and other	(3,061)	(3,228)
Gross deferred tax liabilities	(20,728)	(18,055)
Net deferred tax liability	$ (2,125)	$ (1,089)