Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Interest and dividends received	$ 125,583	$ 120,161
Service charges and other fees received	15,036	18,130
Interest paid	(7,984)	(8,402)
Net cash paid to vendors and employees	(63,504)	(38,837)
Income taxes paid	(35,500)	(38,200)
(Payments to) proceeds from FDIC loss share agreement	(1,372)	312
Net cash provided by operating activities	32,259	53,164
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from redemption of FHLB stock	8,899	11,435
Proceeds from maturity of interest-earning balances from depository institutions	1,494	0
Proceeds from sale of investment securities	14,271	99,155
Proceeds from repayment of investment securities	143,151	249,749
Proceeds from maturity of investment securities	47,199	25,867
Purchases of investment securities	(413,458)	(368,829)
Net decrease in loan and lease finance receivables	184,031	111,102
Proceeds from sales of premises and equipment	663	5
Purchase of premises and equipment	(964)	(1,541)
Proceeds from sales of other real estate owned	2,254	12,872
Cash acquired on purchase of American Security Bank, net of cash paid	50,038	0
Net cash provided by investing activities	37,578	139,815
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in transaction deposits	392,737	69,142
Net decrease in time deposits	(32,172)	(10,807)
Repayment of junior subordinated debentures	0	(41,238)
Net decrease in other borrowings	(69,000)	(26,000)
Net (decrease) increase in customer repurchase agreements	(31,792)	18,397
Cash dividends on common stock	(21,117)	(19,414)
Repurchase of common stock	(4,908)	(61)
Proceeds from exercise of stock options	5,109	780
Tax benefit related to exercise of stock options	796	59
Net cash provided by (used in) financing activities	239,653	(9,142)
NET INCREASE IN CASH AND CASH EQUIVALENTS	309,490	183,837
CASH AND CASH EQUIVALENTS, beginning of period	94,693	98,431
CASH AND CASH EQUIVALENTS, end of period	404,183	282,268
RECONCILIATION OF NET EARNINGS TO NET CASH PROVIDED BY OPERATING ACTIVITIES
Net earnings	54,145	46,081
Adjustments to reconcile net earnings to net cash provided by operating activities:
Gain on sale of loans held-for-sale	(5,330)	0
Gain on sale of investment securities	0	(2,094)
Loss on sale of premises and equipment, net	71	6
Gain on sale of other real estate owned	(117)	(3,053)
Amortization of capitalized prepayment penalty on borrowings	136	136
Increase in bank owned life insurance	(1,161)	(1,322)
Net amortization of premiums and discounts on investment securities	10,044	13,938
Accretion of SJB discount	(3,174)	(7,849)
Provision for loan losses	(15,100)	(6,200)
Valuation adjustment on other real estate owned	0	87
Change in FDIC loss share asset	3,174	7,467
(Payments to) proceeds from FDIC loss share agreement	(1,372)	312
Stock-based compensation	1,531	893
Depreciation and amortization, net	858	1,603
Change in accrued interest receivable	331	193
Change in accrued interest payable	12	(317)
Change in other assets and liabilities	(11,789)	3,283
Total adjustments	(21,886)	7,083
Net cash provided by operating activities	32,259	53,164
Net cash provided by investing activities	37,578	139,815
Net cash provided by (used in) financing activities	239,653	(9,142)
NET INCREASE IN CASH AND CASH EQUIVALENTS	309,490	183,837
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING ACTIVITIES
Securities purchased and not settled	56,430	67,483
Transfer of loans to other real estate owned	$ 478	$ 1,492