NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 14) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans individually evaluated for impairment	$ 184,271	$ 183,477
Covered loans individually evaluated for impairment	112	2,824
Loans collectively evaluated for impairment	17,331,422	15,812,201
Covered loans acquired with deteriorated credit quality	1,978,025	2,141,375
Ending balance	19,568,370	18,139,877
Covered nonaccrual loans	125,021	126,895
MetroCorp
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans acquired with deteriorated credit quality	74,540
Covered loans accounted for under ASC 310-10
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Covered nonaccrual loans	12,800	17,700
Residential
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans individually evaluated for impairment	55,155	56,287
Loans collectively evaluated for impairment	4,292,913	4,129,022
Covered loans acquired with deteriorated credit quality	639,460	681,608
Ending balance	4,988,945	4,866,917
Residential | MetroCorp
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans acquired with deteriorated credit quality	1,417
Commercial Real Estate ("CRE")
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans individually evaluated for impairment	85,593	84,436
Loans collectively evaluated for impairment	5,366,973	4,500,641
Covered loans acquired with deteriorated credit quality	1,043,912	1,140,432
Ending balance	6,563,831	5,725,509
Commercial Real Estate ("CRE") | MetroCorp
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans acquired with deteriorated credit quality	67,353
Commercial and Industrial ("C&I")
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans individually evaluated for impairment	42,781	39,527
Loans collectively evaluated for impairment	6,152,534	5,320,666
Covered loans acquired with deteriorated credit quality	128,730	146,538
Ending balance	6,329,815	5,506,731
Commercial and Industrial ("C&I") | MetroCorp
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans acquired with deteriorated credit quality	5,770
Consumer
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Loans individually evaluated for impairment	742	3,227
Loans collectively evaluated for impairment	1,237,180	1,544,511
Covered loans acquired with deteriorated credit quality	41,659	43,136
Ending balance	1,279,581	1,590,874
Covered Loans under ASC 310-10 Subject to Allowance for Loan Losses
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Covered loans individually evaluated for impairment	112	2,824
Loans collectively evaluated for impairment	281,822	317,361
Ending balance	281,934	320,185
Covered Loans under ASC 310-30 Subject to Allowance for Loan Losses
Recorded investment in total loans receivable related to each balance in the allowance for loan losses
Covered loans acquired with deteriorated credit quality	124,264	129,661
Ending balance	$ 124,264	$ 129,661