Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total Shareholders' Equity [Member]	Non-Controlling Interests [Member]
Balance, beginning of period (in shares) at Dec. 31, 2015		74,530			8,636
Balance, beginning of period at Dec. 31, 2015	$ 3,267,639	$ 4	$ 982,009	$ 2,704,121	$ (477,165)	$ 21,587	$ 3,230,556	$ 37,083
Net income (loss)	182,372			182,642			182,642	(270)
Other comprehensive income	74,140					74,140	74,140
Repurchase of common stock (in shares)					305
Repurchase of common stock	(17,771)				$ (17,771)		(17,771)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		108
Stock options exercised	5,513		5,513				5,513
Non-vested shares awarded, net (in shares)		228
Vesting of non-vested shares (in shares)					15
Vesting of non-vested shares	(95)				$ (95)		(95)
Tax effect from equity compensation, net	589		589				589
Share-based compensation	7,569		7,569				7,569
Cash dividends on common stock	(84,832)			(84,832)			(84,832)
Capital calls and distributions, net	(2,713)							(2,713)
Balance, end of period (in shares) at Sep. 30, 2016		74,866			8,956
Balance, end of period at Sep. 30, 2016	3,432,411	$ 4	995,680	2,801,931	$ (495,031)	95,727	3,398,311	34,100
Balance, beginning of period (in shares) at Dec. 31, 2016		74,993			9,656
Balance, beginning of period at Dec. 31, 2016	3,306,357	$ 4	1,006,535	2,823,334	$ (544,052)	(10,967)	3,274,854	31,503
Net income (loss)	263,320			262,152			262,152	1,168
Other comprehensive income	17,724					17,724	17,724
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		80
Stock options exercised	4,564		4,564				4,564
Non-vested shares awarded, net (in shares)		57
Vesting of non-vested shares (in shares)					17
Vesting of non-vested shares	(1,389)				$ (1,389)		(1,389)
Share-based compensation	17,390		17,390				17,390
Cash dividends on common stock	(86,481)			(86,481)			(86,481)
Capital calls and distributions, net	(7,046)							(7,046)
Balance, end of period (in shares) at Sep. 30, 2017		75,130			9,673
Balance, end of period at Sep. 30, 2017	$ 3,514,439	$ 4	$ 1,028,489	$ 2,999,005	$ (545,441)	$ 6,757	$ 3,488,814	$ 25,625