CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Accumulated Other Comprehensive Loss Member	Treasury Stock Member
Accumulated other comprehensive loss	$ (216,840)
Beginning Balance at Dec. 31, 2017		$ 49,187	$ 120,609	$ 1,944,324	$ (216,840)	$ (369,480)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	118,431
Other Comprehensive Income (Loss), Net of Tax	(22,676)				(22,676)
Dividends paid/declared				(13,231)
Restricted stock			(6,923)			6,923
Stock options exercised			(1,535)			7,896
Other			(725)			725
Share-based compensation			7,599			201
Repurchases of common stock						(46,115)
Ending Balance at Jun. 30, 2018		49,187	119,025	2,047,250	(239,516)	(399,850)
Beginning Balance at Dec. 31, 2017		49,187	120,609	1,944,324	(216,840)	(369,480)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings				118,431
Other Comprehensive Income (Loss), Net of Tax	(71,607)
Ending Balance at Dec. 31, 2018	1,530,781	49,187	118,234	2,191,471	(288,447)	(539,664)
Beginning Balance at Mar. 31, 2018		49,187	116,221	1,979,051	(198,807)	(366,677)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	74,788			74,788
Other Comprehensive Income (Loss), Net of Tax	(40,709)				(40,709)
Dividends paid/declared				(6,589)
Restricted stock			(95)			95
Stock options exercised			(298)			507
Share-based compensation			3,197			12
Repurchases of common stock						(33,787)
Ending Balance at Jun. 30, 2018		49,187	119,025	2,047,250	(239,516)	(399,850)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2014-09 [Member]				(2,274)
Accumulated other comprehensive loss	(288,447)
Beginning Balance at Dec. 31, 2018	1,530,781	49,187	118,234	2,191,471	(288,447)	(539,664)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	135,665			135,665
Other Comprehensive Income (Loss), Net of Tax	12,214				12,214
Dividends paid/declared				(13,690)
Restricted stock			(5,491)			5,491
Stock options exercised			(1,822)			7,233
Other			(661)			661
Share-based compensation			6,575			405
Repurchases of common stock						(25,065)
Ending Balance at Jun. 30, 2019	1,652,296	49,187	116,835	2,339,703	(302,490)	(550,939)
Beginning Balance at Mar. 31, 2019		49,187	114,696	2,266,902	(304,779)	(540,426)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	80,072			80,072
Other Comprehensive Income (Loss), Net of Tax	2,289				2,289
Dividends paid/declared				(7,271)
Stock options exercised			(1,303)			2,038
Share-based compensation			3,442			43
Repurchases of common stock						(12,594)
Ending Balance at Jun. 30, 2019	1,652,296	$ 49,187	$ 116,835	$ 2,339,703	$ (302,490)	$ (550,939)
Accumulated other comprehensive loss	$ (302,490)