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	68,083					68,083
Other comprehensive income	17,062							17,062
Stock compensation costs	3,637				3,637
Tax benefit from stock compensation plans, net	29				29
Issuance of 193,831 and 205,103 shares of common stock pursuant to various stock compensation plans and agreements for the period ended March 31, 2013 and 2012, respectively	1,539				1,539
Cancellation of 22,050 and 47,489 shares of common stock due to forfeitures of issued restricted stock for the period ended March 31, 2013 and 2012, respectively					883		(883)
344,423 and 60,073 shares of restricted stock surrendered due to employee tax liability for the period ended March 31, 2013 and 2012, respectively	(1,313)						(1,313)
Preferred stock dividends	(1,714)					(1,714)
Common stock dividends	(14,791)					(14,791)
Purchase of 3,543,100 and 4,554,827 shares of treasury stock pursuant to the Stock Repurchase Program for the period ended March 31, 2013 and 2012, respectively	(100,978)						(100,978)
BALANCE at Mar. 31, 2012	2,283,297		83,027	157	1,449,971	986,195	(219,175)	(16,878)
BALANCE at Dec. 31, 2012	2,382,122	0	83,027	157	1,464,739	1,151,828	(322,298)	4,669
Increase (Decrease) in Stockholders' Equity
Net income	72,091					72,091
Other comprehensive income	1,516							1,516
Stock compensation costs	2,504				2,504
Tax benefit from stock compensation plans, net	2,602				2,602
Issuance of 193,831 and 205,103 shares of common stock pursuant to various stock compensation plans and agreements for the period ended March 31, 2013 and 2012, respectively	442				442
Cancellation of 22,050 and 47,489 shares of common stock due to forfeitures of issued restricted stock for the period ended March 31, 2013 and 2012, respectively					387		(387)
344,423 and 60,073 shares of restricted stock surrendered due to employee tax liability for the period ended March 31, 2013 and 2012, respectively	(8,365)						(8,365)
Preferred stock dividends	(1,714)					(1,714)
Common stock dividends	(21,079)					(21,079)
Purchase of 3,543,100 and 4,554,827 shares of treasury stock pursuant to the Stock Repurchase Program for the period ended March 31, 2013 and 2012, respectively	(87,000)						(87,000)
BALANCE at Mar. 31, 2013	$ 2,343,119		$ 83,027	$ 157	$ 1,470,674	$ 1,201,126	$ (418,050)	$ 6,185