Guarantor and Non-Guarantor Financial Information - Operating Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 27, 2020	Mar. 28, 2020	Jun. 29, 2019	Mar. 30, 2019	Jun. 27, 2020	Jun. 29, 2019
Net sales	$ 512,539		$ 371,197		$ 961,909	$ 783,931
Cost of goods sold	378,438		279,330		722,892	603,985
Gross profit	134,101		91,867		239,017	179,946
Operating expenses:
Selling, general and administrative expenses	44,347		39,856		84,320	78,153
Amortization expense	4,739		4,601		9,462	9,092
Operating income	85,015		47,410		145,235	92,701
Other income and expenses:
Interest expense, net	24,849		23,179		50,888	46,253
Other [(income) expense]	(701)		(525)		(1,154)	(783)
Income before income tax expense	60,867		24,756		95,501	47,231
Income tax expense	15,956		6,505		22,498	12,189
Net income	44,911	$ 28,092	18,251	$ 16,791	73,003	35,042
Comprehensive income (loss)	46,801		19,957		60,840	38,368
Eliminations
Net sales	(25,551)		(38,723)		(51,974)	(71,181)
Cost of goods sold	(25,551)		(38,723)		(51,974)	(71,181)
Other income and expenses:
Equity in earnings (loss) of subsidiaries	(47,354)		(14,733)		(80,786)	(37,582)
Net income	(47,354)		(14,733)		(80,786)	(37,582)
Comprehensive income (loss)	(48,805)		(16,113)		(67,592)	(40,258)
Parent | Reportable Legal Entities
Other income and expenses:
Equity in earnings (loss) of subsidiaries	44,911		18,251		73,003	35,042
Net income	44,911		18,251		73,003	35,042
Comprehensive income (loss)	46,801		19,957		60,840	38,368
Guarantor Subsidiaries | Reportable Legal Entities
Net sales	488,871		363,329		906,269	753,496
Cost of goods sold	359,737		273,706		681,975	580,006
Gross profit	129,134		89,623		224,294	173,490
Operating expenses:
Selling, general and administrative expenses	42,708		34,887		80,648	74,942
Amortization expense	4,739		4,601		9,462	9,092
Operating income	81,687		50,135		134,184	89,456
Other income and expenses:
Interest expense, net	24,849		23,179		50,888	46,253
Other [(income) expense]	(701)		(525)		(1,154)	(783)
Income before income tax expense	57,539		27,481		84,450	43,986
Income tax expense	15,071		5,712		19,230	11,484
Equity in earnings (loss) of subsidiaries	2,443		(3,518)		7,783	2,540
Net income	44,911		18,251		73,003	35,042
Comprehensive income (loss)	44,692		18,088		72,488	34,717
Non-Guarantor Subsidiaries | Reportable Legal Entities
Net sales	49,219		46,591		107,614	101,616
Cost of goods sold	44,252		44,347		92,891	95,160
Gross profit	4,967		2,244		14,723	6,456
Operating expenses:
Selling, general and administrative expenses	1,639		4,969		3,672	3,211
Operating income	3,328		(2,725)		11,051	3,245
Other income and expenses:
Income before income tax expense	3,328		(2,725)		11,051	3,245
Income tax expense	885		793		3,268	705
Net income	2,443		(3,518)		7,783	2,540
Comprehensive income (loss)	$ 4,113		$ (1,975)		$ (4,896)	$ 5,541