CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (loss)	Treasury Stock	Non- controlling Interest
Beginning Balance (in shares) at Dec. 31, 2015		43,517				1,908
Beginning Balance at Dec. 31, 2015	$ 2,011,093	$ 43,517	$ 440,127	$ 2,016,176	$ (371,124)	$ (119,424)	$ 1,821
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	237,841			237,377			464
Cash dividends ($1.36 per share)	(58,960)			(58,960)
Other comprehensive loss	(66,804)				(66,761)		(43)
Distributions to noncontrolling interest shareholders	(464)						(464)
Acquisition of noncontrolling interest	(9,231)		(6,621)		(832)		(1,778)
Settlement of convertible notes (in shares)		2,168				(430)
Settlement of warrants	3,296	$ 2,168	(32,004)			$ 33,132
Settlement of note hedges associated with convertible notes (in shares)						316
Settlement of note hedges associated with convertible notes	2		86,048			$ (86,046)
Reclassification of convertible notes to mezzanine equity	(1,824)		(1,824)
Shares issued under compensation plans (in shares)		129				(51)
Shares issued under compensation plans	22,492	$ 129	21,074			$ 1,289
Deferred compensation (in shares)						(2)
Deferred compensation	76					$ 76
Ending Balance (in shares) at Dec. 31, 2016		45,814				1,741
Ending Balance at Dec. 31, 2016	2,137,517	$ 45,814	506,800	2,194,593	(438,717)	$ (170,973)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	152,530			152,530
Cash dividends ($1.36 per share)	(61,237)			(61,237)
Other comprehensive loss	173,626				173,626
Settlement of convertible notes (in shares)		928				(503)
Settlement of warrants	4,832	$ 928	(48,375)			$ 52,279
Settlement of note hedges associated with convertible notes (in shares)						516
Settlement of note hedges associated with convertible notes	(7)		112,901			$ (112,908)
Shares issued under compensation plans (in shares)		129				(48)
Shares issued under compensation plans	23,182	$ 129	20,395			$ 2,658
Deferred compensation (in shares)						(2)
Deferred compensation	88					$ 88
Ending Balance (in shares) at Dec. 31, 2017		46,871				1,704
Ending Balance at Dec. 31, 2017	2,430,531	$ 46,871	591,721	2,285,886	(265,091)	$ (228,856)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	200,802			200,802
Cash dividends ($1.36 per share)	(62,165)			(62,165)
Other comprehensive loss	(75,994)				(75,994)
Settlement of convertible notes (in shares)						(412)
Settlement of warrants	(40)		(56,115)			$ 56,075
Shares issued under compensation plans (in shares)		377				(50)
Shares issued under compensation plans	42,899	$ 377	38,756			$ 3,766
Deferred compensation (in shares)						(10)
Deferred compensation	869		399			$ 470
Ending Balance (in shares) at Dec. 31, 2018		47,248				1,232
Ending Balance at Dec. 31, 2018	$ 2,539,978	$ 47,248	$ 574,761	$ 2,427,599	$ (341,085)	$ (168,545)	$ 0