Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 131,461	$ 175,722	$ 163,356
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	28,763	30,310	32,063
Provision for loan losses	73,038	33,840	32,734
Loss (gain) on other real estate owned	635	(105)	4,329
Deferred tax expense	16,685	23,537	40,920
Increase in cash surrender value of life insurance contracts	(9,789)	(11,774)	(11,223)
Writedowns on closed branch transfers to other real estate owned		2,132	12,809
Loss (gain) on disposal of other assets	1,815	(1,282)	130
Net (increase) decrease in loans held for sale	(289)	18,234	29,103
Net amortization of securities premium/discount	21,105	16,977	31,970
Amortization of intangible assets	24,184	26,798	29,635
Amortization of FDIC loss share receivable	5,747	12,102	2,239
Stock-based compensation expense	12,944	13,958	13,079
(Decrease) increase in interest payable and other liabilities	(8,107)	(15,235)	29,553
Net payments from FDIC	14,051	14,395	61,765
Decrease (increase) in FDIC loss share receivable	6,407	5,723	(9,117)
(Increase) decrease in other assets	(93,950)	11,082	(724)
Other, net	7,645	(3,986)	10,911
Net cash provided by operating activities	232,345	352,428	473,532
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale	9,289	1,455	178
Proceeds from maturities of securities available for sale	842,114	283,982	592,147
Purchases of securities available for sale	(1,323,853)	(512,088)	(1,074,744)
Proceeds from maturities of securities held to maturity	538,777	442,559	503,654
Purchases of securities held to maturity	(749,102)	(1,031)	(481,513)
Net decrease (increase) in short-term investments	237,393	(534,108)	1,231,348
Net increase in loans	(1,865,015)	(1,622,867)	(834,933)
Purchase of life insurance contracts		(30,000)
Purchases of property, equipment and intangible assets	(23,804)	(20,449)	(32,029)
Proceeds from sales of property and equipment	14,259	12,235	1,698
Proceeds from sales of other real estate	47,115	59,752	92,662
Other, net	(3,604)	10,101	(2,965)
Net cash provided by (used in) investing activities	(2,276,431)	(1,910,459)	(4,497)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	1,776,081	1,212,315	(383,672)
Net increase in short-term borrowings	272,071	493,613	18,827
Repayments of long-term debt	(157,933)	(35,360)	(35,278)
Issuance of long-term debt	273,565	21,000	24,515
Dividends paid	(77,013)	(80,392)	(81,212)
Repurchase of common stock	(95,613)	(47,618)	(115,000)
Proceeds from exercise of stock options	347	2,488	2,734
Net cash provided by (used in) financing activities	1,991,505	1,566,046	(569,086)
NET (DECREASE) INCREASE IN CASH AND DUE FROM BANKS	(52,581)	8,015	(100,051)
CASH AND DUE FROM BANKS, BEGINNING	356,455	348,440	448,491
CASH AND DUE FROM BANKS, ENDING	303,874	356,455	348,440
SUPPLEMENTAL INFORMATION
Income taxes paid	31,896	24,114	24,052
Interest paid	51,201	38,268	41,996
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 15,462	$ 31,371	51,461
Transfers from available for sale securities to held to maturity securities			$ 1,039,979