Basis of Presentation and Consolidation - Additional Information (Detail) - USD ($) $ in Thousands				3 Months Ended			9 Months Ended		12 Months Ended
	May 10, 2019	Feb. 15, 2019	Sep. 24, 2018	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Apr. 05, 2019
Summary Of Significant Policies [Line Items]
Minimum percentage of investment consolidated							50.00%
Maximum percentage of cost method investments							20.00%
Investment in joint venture				$ 48,936	$ 0		$ 48,936		$ 0
Diluted securities excluded from EPS amount (in shares)				77,215			77,215	0
Unfavorable Regulatory Action
Summary Of Significant Policies [Line Items]
Loss contingency imposed		42.16%
Incurred expense on loss contingency				$ 8,818			$ 26,754
Section 301 Tariffs
Summary Of Significant Policies [Line Items]
Loss contingency imposed	25.00%		10.00%
Incurred expense on loss contingency				6,495			15,892
Loss from Catastrophes | Cost of Sales
Summary Of Significant Policies [Line Items]
Incurred expense on loss contingency						$ 17		$ 1,569	1,569	$ 12,583
Recovered insurance proceeds						$ 504		$ 7,300	$ 7,300	$ 7,000
GRT Acquisition
Summary Of Significant Policies [Line Items]
Goodwill impairment charge					$ 33,827
TBR
Summary Of Significant Policies [Line Items]
Noncontrolling interest											35.00%
TBR | GRT Acquisition
Summary Of Significant Policies [Line Items]
Investment in joint venture				$ 49,001			$ 49,001
TBR | GRT Acquisition | Minimum
Summary Of Significant Policies [Line Items]
Investment in joint venture											$ 220,000
TBR | GRT Acquisition | Maximum
Summary Of Significant Policies [Line Items]
Investment in joint venture											$ 240,000