STOCKHOLDERS' EQUITY - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) numberofstocks $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) shares	Mar. 31, 2015 shares
Class Of Stock [Line Items]
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, par value | $ / shares	$ 0.10	$ 0.10
Common stock, shares issued	218,089,106	216,051,128
Common stock, shares outstanding	217,011,555	215,088,698
Granted shares of restricted stock	1,785,137
Corporation has authorized shares of preferred stock	50,000,000	50,000,000
Preferred stock, par value | $ / shares	$ 1.00
Number of preferred stock series | numberofstocks	5
Stock repurchase plan treasury stock	1,077,551	962,430
Repurchased of common stock	115,121			50,708
Liquidation value per share | $ / shares	$ 25
Legal surplus reserve amount | $	$ 42.8
Conversion Of Stock Shares Issued1			852,831
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number		2,968,461
Trust Preferred Securities Exchanged Liquidation Value | $			$ 5.3
Legal Surplus Amount Additions | $		$ 2.8
Minimum [Member]
Class Of Stock [Line Items]
Restricted stock lapse, maximum				3 months
Maximum [Member]
Class Of Stock [Line Items]
Restricted stock lapse, maximum				3 years
Omnibus Plan [Member]
Class Of Stock [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number	4,375,851
Restricted Stock [Member]
Class Of Stock [Line Items]
Repurchased of common stock	35,167			22,525
FirstBank [Member]
Class Of Stock [Line Items]
Legal surplus reserve rate	10.00%
Original amount contributed in percentage	20.00%
Series A Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage	7.125%
Series B Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage	8.35%
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage	7.40%
Series D Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage	7.25%
Series E Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage	7.00%