PARENT COMPANY CONDENSED FINANCIAL STATEMENTS (Details) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 1,039,885	$ 895,820	$ 1,323,106	$ 1,431,185
Investment securities available-for-sale	2,626,365us-gaap_AvailableForSaleSecurities	2,733,797us-gaap_AvailableForSaleSecurities
Other assets	1,001,770us-gaap_OtherAssets	784,907us-gaap_OtherAssets
TOTAL	28,738,049us-gaap_Assets	24,730,068us-gaap_Assets	22,536,110us-gaap_Assets
LIABILITIES AND STOCKHOLDERS' EQUITY
Long-term debt	225,848us-gaap_LongTermDebt	226,868us-gaap_LongTermDebt
Total liabilities	25,887,481us-gaap_Liabilities	22,365,843us-gaap_Liabilities
STOCKHOLDERS' EQUITY
Common stock, $0.001 par value, 200,000,000 shares authorized; 163,772,218 and 163,098,008 shares issued in 2014 and 2013, respectively; 143,582,229 and 137,630,896 shares outstanding in 2014 and 2013, respectively.	164us-gaap_CommonStockValue	163us-gaap_CommonStockValue
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000us-gaap_CommonStockSharesAuthorized	200,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	163,772,218us-gaap_CommonStockSharesIssued	163,098,008us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	143,582,229us-gaap_CommonStockSharesOutstanding	137,630,896us-gaap_CommonStockSharesOutstanding
Additional paid in capital	1,677,767us-gaap_AdditionalPaidInCapital	1,571,670us-gaap_AdditionalPaidInCapital
Retained earnings	1,598,598	1,360,130
Treasury stock, at cost-20,189,989 shares in 2014 and 25,467,112 shares in 2013	(430,198)us-gaap_TreasuryStockValue	(537,279)us-gaap_TreasuryStockValue
Treasury stock, shares	20,189,989us-gaap_TreasuryStockShares	25,467,112us-gaap_TreasuryStockShares
Accumulated other comprehensive income (loss), net of tax	4,237	(30,459)	4,669	(33,940)
Total stockholders' equity	2,850,568us-gaap_StockholdersEquity	2,364,225us-gaap_StockholdersEquity	2,382,122us-gaap_StockholdersEquity	2,311,743us-gaap_StockholdersEquity
TOTAL	28,738,049	24,730,068
Parent Company
ASSETS
Cash and cash equivalents	211,053	79,934	64,489	9,287
Investment securities available-for-sale	8,370	69,796
Investment in subsidiaries	2,841,684	2,400,937
Other investments	41,054	21,371
Other assets	22,474	37,037
TOTAL	3,124,635	2,609,075
LIABILITIES AND STOCKHOLDERS' EQUITY
Long-term debt	225,848	226,868
Other liabilities	48,219	17,982
Total liabilities	274,067	244,850
STOCKHOLDERS' EQUITY
Common stock, $0.001 par value, 200,000,000 shares authorized; 163,772,218 and 163,098,008 shares issued in 2014 and 2013, respectively; 143,582,229 and 137,630,896 shares outstanding in 2014 and 2013, respectively.	164	163
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	163,772,218	163,098,008
Common stock, shares outstanding	143,582,229	137,630,896
Additional paid in capital	1,677,767	1,571,670
Retained earnings	1,598,598	1,360,130
Treasury stock, at cost-20,189,989 shares in 2014 and 25,467,112 shares in 2013	(430,198)	(537,279)
Treasury stock, shares	20,189,989	25,467,112
Accumulated other comprehensive income (loss), net of tax	4,237	(30,459)
Total stockholders' equity	2,850,568	2,364,225
TOTAL	$ 3,124,635	$ 2,609,075

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 14

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e681-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 14A

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 31

-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3