Supplemental equity information - Computation of Diluted Income Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 29, 2019	Sep. 30, 2020	Sep. 29, 2019
Stock warrants
Share-based Compensation Arrangement by Share-based Payment Award
Computation of diluted income per share (in shares)	1,362	1,362	1,362	1,362
Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Computation of diluted income per share (in shares)	6,068	2,905	6,068	2,905
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award
Computation of diluted income per share (in shares)	7,130	446	7,130	446