Business Segment Information - Summary of Net Sales by Geographic Destination (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 121,078	$ 111,708	$ 111,547	$ 108,709	$ 116,896	$ 105,247	$ 108,942	$ 102,738	$ 453,042	$ 433,823	$ 409,788
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									355,353	345,145	316,873
Italy [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									19,331	17,059	16,664
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									11,606	7,063	6,448
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									8,731	8,725	10,362
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									7,120	10,356	11,334
Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									$ 50,901	$ 45,475	$ 48,107