CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive, Net Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Beginning balance at Dec. 31, 2018	$ 6,547	$ 823,347	$ (33,511)	$ 2,723,592	$ (306,788)	$ 3,114	$ 3,216,301
Beginning balance (in shares) at Dec. 31, 2018	65,472				(5,608)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises	$ 0	52	0	0	$ 1,364	0	1,416
Stock option exercises (in shares)	0				25
Issuance of stock for equity awards, net of forfeitures	$ 0	(802)	0	0	$ 802	0	0
Issuance of stock for equity awards, net of forfeitures (in shares)	0				14
Tax withholdings on equity award vesting	$ 0	0	0	0	$ (2,003)	0	(2,003)
Tax withholdings on equity award vesting (in shares)	0				(30)
Amortization of unearned share-based compensation	$ 0	4,900	0	0	$ 0	0	4,900
Total comprehensive income (loss), net of taxes	0	0	540	44,296	0	161	44,997
Return of investment to noncontrolling interests	0	0	0	0	0	(203)	(203)
Ending balance at Mar. 31, 2019	$ 6,547	827,497	(32,971)	2,767,888	$ (306,625)	3,072	3,265,408
Ending balance (in shares) at Mar. 31, 2019	65,472				(5,599)
Beginning balance at Dec. 31, 2019	$ 6,547	835,899	(37,799)	2,865,939	$ (301,963)	2,969	3,371,592
Beginning balance (in shares) at Dec. 31, 2019	65,472				(5,513)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises		26	0	0	$ 327	0	353
Stock option exercises (in shares)	0				15
Issuance of stock for equity awards, net of forfeitures		(3,377)	0	0	$ 3,377	0	0
Issuance of stock for equity awards, net of forfeitures (in shares)	0				61
Tax withholdings on equity award vesting		0	0	0	$ (3,165)	0	(3,165)
Tax withholdings on equity award vesting (in shares)					(38)
Amortization of unearned share-based compensation	$ 0	5,331	0	0	$ 0	0	5,331
Total comprehensive income (loss), net of taxes	0	0	(1,192)	(347,241)	0	278	(348,155)
Return of investment to noncontrolling interests	0	0	0	0	0	(202)	(202)
Ending balance at Mar. 31, 2020	$ 6,547	$ 837,879	$ (38,991)	$ 2,518,698	$ (301,424)	$ 3,045	$ 3,025,754
Ending balance (in shares) at Mar. 31, 2020	65,472				(5,475)