Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Thousands				3 Months Ended				9 Months Ended
	Nov. 07, 2018	Jan. 31, 2018	Jul. 31, 2017	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Equity, Class of Treasury Stock [Line Items]
Amount available under repurchase plan				$ 7,200,000				$ 7,200,000
Total authorized amount under stock repurchase plan				$ 142,200,000				$ 142,200,000
Shares repurchased for employee net vesting obligations, shares				8			68	191	262
Shares repurchased for employee net vesting obligations, value				$ 100,000			$ 1,100,000	$ 3,300,000	$ 4,300,000
Annual cash dividend per share		$ 0.30	$ 0.26
Dividend payment		$ 4,700,000	$ 4,600,000		$ 5,400,000
Dividend declared					$ 0.17	$ 0.34
Dividend declared, date of record					Jun. 29, 2018
Dividend declared, date of payment					Jul. 11, 2018
Subsequent Event [Member]
Equity, Class of Treasury Stock [Line Items]
Dividend declared	$ 0.17
Dividend declared, date of record	Dec. 21, 2018
Dividend declared, date of payment	Jan. 04, 2019
Share Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock							182	53	748
Purchase price per share							$ 13.73	$ 18.33	$ 15.11
Total cost							$ 2,500,000	$ 1,000,000	$ 11,300,000
Stock Appreciation Rights (SARs) [Member]
Equity, Class of Treasury Stock [Line Items]
SARs outstanding				2,900				2,900
Exercise price				$ 4.00				$ 4.00
Expiration date								Feb. 28, 2022