BUSINESS COMBINATION (Details) - USD ($) $ in Thousands		9 Months Ended
	Jan. 17, 2014	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Purchase consideration
Consideration transferred in the acquisition (in shares)		5,583,093
Issuance of 5,583,093 shares pursuant to MetroCorp Bancshares, Inc. acquisition		$ 190,830
Assets acquired and liabilities assumed
Goodwill		$ 458,467	$ 469,433	$ 469,433
MetroCorp
Purchase consideration
Percentage of purchase consideration satisfied in stock	66.67%
Percentage of purchase consideration satisfied in cash	33.33%
Fair value of the consideration transferred	$ 291,400
Consideration transferred in the acquisition (in shares)	5,583,093
Issuance of 5,583,093 shares pursuant to MetroCorp Bancshares, Inc. acquisition	$ 190,800
Consideration transferred in cash	89,400
Additional cash given to acquiree's stock option holders as part of consideration transferred	2,400
Fair value of warrants assumed as part of consideration transferred	8,800
Assets acquired and liabilities assumed
Fair value of assets acquired	1,700,000
Fair value of liabilities acquired	1,410,000
Goodwill	$ 121,000			132,000
MetroCorp | Adjustments
Assets acquired and liabilities assumed
Deferred tax assets				10,300
Bank owned life insurance				$ 700