INVESTMENTS IN QUALIFIED AFFORDABLE HOUSING PARTNERSHIPS, NET, TAX CREDIT AND OTHER INVESTMENTS (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014		Dec. 31, 2014
Impact of new accounting guidance
Investment in qualified affordable housing partnerships, net	$ 182,719			$ 178,962	[1]
Other assets - Deferred tax assets				389,601
Retained earnings	1,675,234			1,604,141	[1]
Noninterest expense - Amortization of tax credit and other investments	6,299	1,492	[1]
Income before taxes	146,826	116,163	[1]
Provision for income taxes	46,799	41,992	[1]
Net income	100,027	74,171	[1]
EARNINGS PER SHARE
BASIC (in dollars per share)	$ 0.70	$ 0.52	[1]
DILUTED (in dollars per share)	$ 0.69	$ 0.52	[1]
Previously Reported
Impact of new accounting guidance
Investment in qualified affordable housing partnerships, net				178,652
Other assets - Deferred tax assets				384,367
Retained earnings				1,598,598
Noninterest expense - Amortization of tax credit and other investments		5,964
Income before taxes		111,690
Provision for income taxes		34,949
Net income		$ 76,741
EARNINGS PER SHARE
BASIC (in dollars per share)		$ 0.54
DILUTED (in dollars per share)		$ 0.54

[1] Prior periods were restated to reflect the retrospective application of adopting the new accounting guidance related to the Company?s investments in qualified affordable housing projects Accounting Standard Update ("ASU") 2014-01. See Note 10 of the Notes to Consolidated Financial Statements for additional information.