Stockholders' Equity - Schedule of Share Repurchase Activity under Share Repurchase Programs (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Dec. 31, 2017
Equity [Abstract]
Number of common shares acquired	719,004	3,249,204	8,411,575	9,136,468
Average price per common share acquired	$ 21.29	$ 22.16	$ 22.98	$ 21.01
Total cost of common shares acquired	$ 15,307	$ 72,000	$ 193,307	$ 192,000	$ 203,392

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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Period Type:	duration