GOODWILL AND OTHER INTANGIBLES - Gross Amount and Accumulated Amortization of Other Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2012	Jun. 30, 2012
Finite Lived Intangible Assets [Line Items]
Gross amount					$ 24,500
Core Deposits [Member]
Finite Lived Intangible Assets [Line Items]
Gross amount		$ 51,664	$ 45,844
Finite lived Intangible Assets Acquired 1		0	5,820
Accumulated amortization		(44,466)	(42,498)
Finite Lived Intangible Assets Net		$ 7,198	$ 9,166
Remaining amortization period		8 years 1 month 6 days	9 years
Purchased Credit Card Relationship Intangible [Member]
Finite Lived Intangible Assets [Line Items]
Gross amount		$ 24,465	$ 24,465
Finite lived Intangible Assets Acquired 1				$ 24,500
Accumulated amortization		(13,934)	(11,146)
Finite Lived Intangible Assets Net		$ 10,531	$ 13,319
Remaining amortization period		5 years	5 years 9 months 18 days
Customer Related Intangible Assets Member
Finite Lived Intangible Assets [Line Items]
Gross amount		$ 1,067	$ 0
Finite lived Intangible Assets Acquired 1	$ 1,100
Accumulated amortization		(140)	0
Finite Lived Intangible Assets Net		$ 927	$ 0
Remaining amortization period		6 years 1 month 6 days	0 years