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	130,021				130,844			(823)
Other comprehensive income (loss)	74,583						74,583
Distributions to non-controlling interest	(554)							(554)
Issuance of preferred stock	144,816	144,816
Purchase of treasury stock	(208,989)					$ (208,989)
Accelerated share repurchase forward contract	(60,000)			$ (60,000)
Issuance of stock under purchase and equity compensation plans	5,241			(10,671)		15,912
Net tax benefit related to equity compensation plans	1,091			1,091
Stock-based compensation	4,468			4,468
Cash dividends per share, Common Stock, Cash	(42,921)				(42,921)
Balance at Jun. 30, 2014	2,262,153	144,816	$ 481,224	1,214,836	537,759	(203,174)	84,314	2,378
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	137,337				135,408			1,929
Other comprehensive income (loss)	(13,304)						(13,304)
Distributions to non-controlling interest	(543)							(543)
Purchase of treasury stock	(143,575)					(143,575)
Accelerated share repurchase forward contract	(20,000)			(20,000)
Settlement of Accelerated Share Repurchase Forward Contract	(60,000)			(60,000)
Issuance of stock under purchase and equity compensation plans	1,890			(14,682)		16,572
Net tax benefit related to equity compensation plans	1,662			1,662
Stock-based compensation	5,252			5,252
Cash dividends per share, Common Stock, Cash	(43,105)				(43,105)
Dividends per share, Preferred Stock, Cash	(4,500)				(4,500)
Balance at Jun. 30, 2015	$ 2,315,360	$ 144,784	$ 484,155	$ 1,261,307	$ 514,451	$ (143,565)	$ 48,789	$ 5,439