Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						12 Months Ended
	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 15, 2017
Equity [Line Items]
Dividends declared per share		$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.07
Dividends, Common Stock, Cash							$ 39,722	$ 9,896
Common Stock, Dividends, Per Share, Declared							$ 0.28	$ 0.07	$ 0
Stock Repurchase Program, Authorized Amount		$ 350,000					$ 350,000				$ 100,000
Additional stock repurchase authorization		$ 250,000					250,000
Stock Repurchased and Retired During Period, Value							179,315	$ 28,000	$ 7,573
Payments for Repurchase of Common Stock							$ 173,781	28,000	$ 7,573
Shares absorbed into plan										5,700
Term of plan, in years							10 years
Weighted average remaining contractual term option outstanding							4 years 5 months
Weighted average remaining contractual term option exercisable							3 years 6 months
Total pre-tax intrinsic value of stock options exercised							$ 16,700	$ 4,800
Total pre-tax intrinsic value based on the closing stock price		$ 27.90					$ 27.90
Intrinsic value of stock options outstanding		$ 14,600					$ 14,600
Intrinsic value of stock options exercisable		$ 8,000					$ 8,000
Share-based payment awards in the form of stock option awards							296	335	549
Contractual term of stock options (in years)							7 years
Shares available for future grants		8,700				8,800	8,700	8,800	9,400
Weighted average remaining contractual term for unvested restricted shares, in years							1 year 11 months	2 years 1 month
performance shares granted							200	100	200
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition							2 years 5 months
Minimum
Equity [Line Items]
Vesting period, in years							3 years
Maximum
Equity [Line Items]
Vesting period, in years							4 years
Unvested Stock Options
Equity [Line Items]
Total compensation cost not yet recognized		$ 3,000					$ 3,000
Performance Stock
Equity [Line Items]
Total compensation cost not yet recognized		2,200					2,200
Restricted Stock
Equity [Line Items]
Total compensation cost not yet recognized		$ 20,600					$ 20,600
Employee Stock Purchase Plan
Equity [Line Items]
Percentage of employee contribution from compensation							10.00%
Rate of discount from the fair market value							15.00%
Shares available for future grants		1,900					1,900
Shares purchase by employees							200	200	300
Weighted-average price per share paid by the employees		$ 24.86				$ 16.92	$ 24.86	$ 16.92	$ 11.56
Subsequent Event [Member]
Equity [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.07