Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-Controlling Interest [Member]
Balance at Dec. 31, 2013	$ 2,214,397	$ 0	$ 481,224	$ 1,279,948	$ 449,836	$ (10,097)	$ 9,731	$ 3,755
Net income	199,042				199,029			13
Other comprehensive income (loss)	50,500						50,500
Distributions to non-controlling interest	(730)							(730)
Issuance of preferred stock	144,784	144,784
Purchase of treasury stock	(69,040)					$ (69,040)
Accelerated share repurchase agreement	(200,000)			$ (60,000)		(140,000)
Issuance of stock under purchase and equity compensation plans	7,203			(12,304)		19,507
Net tax benefit related to equity compensation plans	1,457			1,457
Stock-based compensation	6,631			6,631
Cash dividends per share, Common Stock, Cash	(63,575)				(63,575)
Dividends per share, Preferred Stock, Cash	(1,800)				(1,800)
Balance at Sep. 30, 2014	2,288,869	144,784	$ 481,224	1,215,732	583,490	(199,630)	60,231	3,038
Balance at Dec. 31, 2014	2,334,246	144,784	484,155	1,229,075	426,648	(16,562)	62,093	4,053
Net income	202,550				200,020			2,530
Other comprehensive income (loss)	3,543						3,543
Distributions to non-controlling interest	(845)							(845)
Purchase of treasury stock	(9,147)					(9,147)
Accelerated share repurchase agreement	(100,000)			(20,000)		(80,000)
Settlement of accelerated share repurchase agreements	0			80,000		(80,000)
Issuance of stock under purchase and equity compensation plans	1,914			(15,302)		17,216
Net tax benefit related to equity compensation plans	1,871			1,871
Stock-based compensation	7,702			7,702
Cash dividends per share, Common Stock, Cash	(64,041)				(64,041)
Dividends per share, Preferred Stock, Cash	(6,750)				(6,750)
Balance at Sep. 30, 2015	$ 2,371,043	$ 144,784	$ 484,155	$ 1,283,346	$ 555,877	$ (168,493)	$ 65,636	$ 5,738