CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance, shares at Dec. 31, 2017		181,286,547
Balance, beginning of period at Dec. 31, 2017	$ 1,844,277	$ 1,813	$ 1,422,808	$ 1,607,570	$ (500,049)	$ (687,865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	174,763			174,763
Total other comprehensive income, net of tax	93,445				93,445
Dividends	(62,731)			(62,731)
Repurchase of common stock	(72,968)					(72,968)
Share-based compensation (in shares)		489,896
Share-based compensation	13,139	$ 5	9,884			3,250
Ending Balance, shares at Apr. 01, 2018		181,776,443
Balance, end of period at Apr. 01, 2018	1,995,949	$ 1,818	1,432,692	1,725,626	(406,604)	(757,583)
Beginning Balance, shares at Dec. 31, 2017		181,286,547
Balance, beginning of period at Dec. 31, 2017	1,844,277	$ 1,813	1,422,808	1,607,570	(500,049)	(687,865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	417,101
Total other comprehensive income, net of tax	103,285				103,285
Ending Balance, shares at Jul. 01, 2018		181,790,087
Balance, end of period at Jul. 01, 2018	2,161,526	$ 1,818	1,442,580	1,906,015	(396,764)	(792,123)
Beginning Balance, shares at Apr. 01, 2018		181,776,443
Balance, beginning of period at Apr. 01, 2018	1,995,949	$ 1,818	1,432,692	1,725,626	(406,604)	(757,583)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	242,338			242,338
Total other comprehensive income, net of tax	9,840				9,840
Dividends	(61,949)			(61,949)
Repurchase of common stock	(38,259)					(38,259)
Share-based compensation (in shares)		13,644
Share-based compensation	13,607	$ 0	9,888			3,719
Ending Balance, shares at Jul. 01, 2018		181,790,087
Balance, end of period at Jul. 01, 2018	2,161,526	$ 1,818	1,442,580	1,906,015	(396,764)	(792,123)
Beginning Balance, shares at Dec. 31, 2018		181,931,225
Balance, beginning of period at Dec. 31, 2018	1,773,949	$ 1,819	1,459,620	2,007,583	(629,684)	(1,065,389)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,945			127,945
Total other comprehensive income, net of tax	7,633				7,633
Dividends	(60,859)			(60,859)
Repurchase of common stock	(61,712)					(61,712)
Share-based compensation (in shares)		702,687
Share-based compensation	10,655	$ 7	5,961			4,687
Ending Balance, shares at Mar. 31, 2019		182,633,912
Balance, end of period at Mar. 31, 2019	1,797,611	$ 1,826	1,465,581	2,074,669	(622,051)	(1,122,414)
Beginning Balance, shares at Dec. 31, 2018		181,931,225
Balance, beginning of period at Dec. 31, 2018	1,773,949	$ 1,819	1,459,620	2,007,583	(629,684)	(1,065,389)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	323,576
Total other comprehensive income, net of tax	14,723				14,723
Ending Balance, shares at Jun. 30, 2019		182,643,250
Balance, end of period at Jun. 30, 2019	1,910,641	$ 1,827	1,474,819	2,210,318	(614,961)	(1,161,362)
Beginning Balance, shares at Mar. 31, 2019		182,633,912
Balance, beginning of period at Mar. 31, 2019	1,797,611	$ 1,826	1,465,581	2,074,669	(622,051)	(1,122,414)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	195,631			195,631
Total other comprehensive income, net of tax	7,090				7,090
Dividends	(59,982)			(59,982)
Repurchase of common stock	(42,908)					(42,908)
Share-based compensation (in shares)		9,338
Share-based compensation	13,199	$ 1	9,238			3,960
Ending Balance, shares at Jun. 30, 2019		182,643,250
Balance, end of period at Jun. 30, 2019	$ 1,910,641	$ 1,827	$ 1,474,819	$ 2,210,318	$ (614,961)	$ (1,161,362)