CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent	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
Total other comprehensive loss, 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, 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 loss, 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)