CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock Member	Preferred Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Treasury Stock Member	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2013	$ 4,626,150	$ 1,034	$ 50,160	$ 4,170,152	$ 594,430	$ (881)	$ (188,745)
Net Income	86,409				86,409
Issuance of stock	1,666	1		1,665
Dividends Abstract
Dividends, Preferred Stock, Cash	(931)				(931)
Treasury Stock Value Acquired Cost Method	(17)					(17)
Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent	32,470						32,470
Ending Balance at Mar. 31, 2014	4,745,747	1,035	50,160	4,171,817	679,908	(898)	(156,275)
Beginning Balance at Dec. 31, 2014	4,267,382	1,036	50,160	4,196,458	253,717	(4,117)	(229,872)
Net Income	74,826				74,826
Issuance of stock	1,406	1		1,405
Adjustments To Additional Paid In Capital Sharebased Compensation And Exercise Of Stock Options	69			69
Dividends Abstract
Dividends, Preferred Stock, Cash	(930)				(930)
Stock Issued During Period, Value, Treasury Stock Reissued	18					18
Treasury Stock Value Acquired Cost Method	(1,123)					(1,123)
Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent	35,472						35,472
Ending Balance at Mar. 31, 2015	$ 4,377,120	$ 1,037	$ 50,160	$ 4,197,932	$ 327,613	$ (5,222)	$ (194,400)