CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Additional Paid In Capital Preferred Stock	Common Stock	Additional Paid In Capital Common Stock	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss), Net of Tax
BALANCE at Dec. 31, 2011	$ 2,311,743		$ 83,027	$ 157	$ 1,443,883	$ 934,617	$ (116,001)	$ (33,940)
Increase (Decrease) in Stockholders' Equity
Net income	138,640					138,640
Other comprehensive income (loss)	18,017							18,017
Stock compensation costs	7,773				7,773
Tax benefit from stock compensation plans, net	157				157
Issuance of 245,261 and 274,430 shares of common stock pursuant to various stock compensation plans and agreements for the period ended June 30, 2013 and 2012, respectively	2,678				2,678
Cancellation of 44,793 and 108,662 shares of common stock due to forfeitures of issued restricted stock for the period ended June 30, 2013 and 2012, respectively					1,870		(1,870)
356,426 and 63,636 shares of restricted stock surrendered due to employee tax liability for the period ended June 30, 2013 and 2012, respectively	(1,396)						(1,396)
Preferred stock dividends	(3,428)					(3,428)
Common stock dividends	(29,294)					(29,294)
Purchase of 8,026,807 and 6,784,227 shares of treasury stock pursuant to the Stock Repurchase Program for the period ended June 30, 2013 and 2012, respectively	(149,950)						(149,950)
BALANCE at Jun. 30, 2012	2,294,940		83,027	157	1,456,361	1,040,535	(269,217)	(15,923)
BALANCE at Dec. 31, 2012	2,382,122		83,027	157	1,464,739	1,151,828	(322,298)	4,669
Increase (Decrease) in Stockholders' Equity
Net income	146,106					146,106
Other comprehensive income (loss)	(26,347)							(26,347)
Stock compensation costs	5,898				5,898
Tax benefit from stock compensation plans, net	2,803				2,803
Issuance of 245,261 and 274,430 shares of common stock pursuant to various stock compensation plans and agreements for the period ended June 30, 2013 and 2012, respectively	1,150				1,150
Cancellation of 44,793 and 108,662 shares of common stock due to forfeitures of issued restricted stock for the period ended June 30, 2013 and 2012, respectively					804		(804)
356,426 and 63,636 shares of restricted stock surrendered due to employee tax liability for the period ended June 30, 2013 and 2012, respectively	(8,667)						(8,667)
Preferred stock dividends	(3,428)					(3,428)
Common stock dividends	(41,694)					(41,694)
Conversion of 85,710 shares of Series A preferred stock into 5,594,080 shares of common stock			(83,027)	6	83,021
Purchase of 8,026,807 and 6,784,227 shares of treasury stock pursuant to the Stock Repurchase Program for the period ended June 30, 2013 and 2012, respectively	(199,992)						(199,992)
BALANCE at Jun. 30, 2013	$ 2,257,951	$ 0		$ 163	$ 1,558,415	$ 1,252,812	$ (531,761)	$ (21,678)