INCOME TAXES (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
INCOME TAXES
Tax credits generated from investments in affordable housing partnerships and other investments									$ 85,700,000	$ 35,000,000	$ 18,700,000
Net deferred tax assets	384,367,000				255,530,000				384,367,000	255,530,000
Current income tax expense (benefit):
Federal									153,211,000	131,236,000	148,572,000
State									70,527,000	44,389,000	2,316,000
Foreign									3,846,000	208,000	5,704,000
Total current income tax expense (benefit)									227,584,000	175,833,000	156,592,000
Deferred income tax (benefit) expense:
Federal									(116,241,000)	(32,963,000)	(38,749,000)
State									(37,665,000)	(13,677,000)	26,099,000
Foreign									(706,000)	1,612,000
Total deferred income tax (benefit) expense									(154,612,000)	(45,028,000)	(12,650,000)
Provision for income taxes	$ 20,049,000	$ (13,644,000)	$ 31,618,000	$ 34,949,000	$ 22,782,000	$ 35,749,000	$ 37,855,000	$ 34,419,000	$ 72,972,000	$ 130,805,000	$ 143,942,000
Difference between the effective tax rate implicit in the consolidated financial statements and the statutory federal income tax rate
Federal income tax provision at statutory rate (as a percent)									35.00%	35.00%	35.00%
State franchise taxes, net of federal tax effect (as a percent)									5.10%	4.70%	4.30%
Tax credits (as a percent)									(21.50%)	(8.40%)	(5.30%)
Other, net (as a percent)									(1.00%)	(0.60%)	(0.20%)
Effective income tax rate (as a percent)									17.60%	30.70%	33.80%