Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Preferred shares	Additional Paid-in Capital [Member]	Accumulated other comprehensive loss	Currency translation adjustment	Unfunded pension obligation	Unrealized gain on investments	Retained earnings	Common shares held in treasury	Noncontrolling interests
Balance at beginning of year at Dec. 31, 2012		$ 85,460	$ 35,750	$ 3,861,844	$ 10,597	$ 32,755	$ (27,370)	$ 5,212	$ 4,952,002	$ (2,012,157)
Issuance of common shares		1,197		26,444
Issuance of preferred shares			10,000	231,265
Redemption of preferred shares			(11,600)	(269,265)
Stock compensation expense, net of taxes paid				51,339
Change in currency translation adjustment	$ (31,778)					(31,778)
Change in net unrealized gain on designated net investment hedge						0
Change in unfunded pension obligation, net of tax	9,861						9,861
Change in unrealized losses on investments, net of tax	(918)							(918)
Net income	673,442								673,442
Net income attributable to noncontrolling interests	(9,434)								(9,434)
Repurchase of common shares	(695,300)									(695,304)
Reissuance of common shares									0	0
Dividends on common shares									(142,217)
Dividends on preferred shares	(57,861)								(57,861)
Loss on redemption of preferred shares	(9,135)								(9,135)
Balance at end of year at Dec. 31, 2013	6,709,532	86,657	34,150	3,901,627	(12,238)	977	(17,509)	4,294	5,406,797	(2,707,461)
Noncontrolling interests											$ 56,627
Total shareholders' equity	6,766,159
Issuance of common shares		580		22,519
Issuance of preferred shares			0	0
Redemption of preferred shares			0	0
Stock compensation expense, net of taxes paid				25,519
Change in currency translation adjustment	(8,892)					(8,892)
Change in net unrealized gain on designated net investment hedge						0
Change in unfunded pension obligation, net of tax	(12,067)						(12,067)
Change in unrealized losses on investments, net of tax	(886)							(886)
Net income	1,068,113								1,068,113
Net income attributable to noncontrolling interests	(13,139)								(13,139)
Repurchase of common shares	(551,400)									(551,409)
Reissuance of common shares									0	0
Dividends on common shares									(134,225)
Dividends on preferred shares	(56,735)								(56,735)
Loss on redemption of preferred shares	0								0
Balance at end of year at Dec. 31, 2014	7,048,910	87,237	34,150	3,949,665	(34,083)	(7,915)	(29,576)	3,408	6,270,811	(3,258,870)
Noncontrolling interests	55,501										55,501
Total shareholders' equity	7,104,411
Issuance of common shares		0		0
Issuance of preferred shares			0	0
Redemption of preferred shares			0	0
Stock compensation expense, net of taxes paid				32,482
Change in currency translation adjustment	(46,055)					(36,750)
Change in net unrealized gain on designated net investment hedge						(9,305)
Change in unfunded pension obligation, net of tax	(2,285)						(2,285)
Change in unrealized losses on investments, net of tax	(860)							(860)
Net income	107,150								107,150
Net income attributable to noncontrolling interests	(2,769)								(2,769)
Repurchase of common shares	(59,300)									(59,266)
Reissuance of common shares									(38,051)	51,584
Dividends on common shares									(133,604)
Dividends on preferred shares	(56,735)								(56,735)
Loss on redemption of preferred shares	0								0
Balance at end of year at Dec. 31, 2015	6,900,501	$ 87,237	$ 34,150	$ 3,982,147	$ (83,283)	$ (53,970)	$ (31,861)	$ 2,548	$ 6,146,802	$ (3,266,552)
Noncontrolling interests	2,450										$ 2,450
Total shareholders' equity	$ 6,902,951