LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Allowance for Loan and Lease Losses and Recorded Investment Excluding Accrued Interest in Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	$ 35,533	$ 29,480	$ 18,805
Charge-offs	(2,618)	(1,942)	(923)
Recoveries	2,258	526	1,235
Provision	5,271	7,469
Balance at end of year	40,444	35,533	29,480
Individually evaluated for impairment				$ 243	$ 369
Collectively evaluated for impairment				40,097	34,958
Total ending allowance balance	35,533	29,480	18,805	40,444	35,533
Loans:
Individually evaluated for impairment				13,352	34,283
Collectively evaluated for impairment				5,879,574	4,437,380
Total ending loan balances				6,034,752	5,184,394
PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	206
Balance at end of year	104	206
Total ending allowance balance	206	206		104	206
Loans:
Total ending loan balances				141,826	712,731
Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	5,850	6,910
Charge-offs	(166)	(33)
Recoveries	225	8
Provision	1,675	(1,035)
Balance at end of year	7,584	5,850	6,910
Individually evaluated for impairment				0	38
Collectively evaluated for impairment				7,584	5,754
Total ending allowance balance	5,850	6,910	6,910	7,584	5,850
Loans:
Individually evaluated for impairment				2,429	7,159
Collectively evaluated for impairment				1,515,771	868,987
Total ending loan balances				1,522,960	876,999
Commercial | Commercial and industrial | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	58
Balance at end of year	0	58
Total ending allowance balance	58	58		0	58
Loans:
Total ending loan balances				4,760	853
Commercial | Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	4,252	3,840
Charge-offs	(414)	(259)
Recoveries	807	132
Provision	822	539
Balance at end of year	5,467	4,252	3,840
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				5,462	4,140
Total ending allowance balance	4,252	3,840	3,840	5,467	4,252
Loans:
Individually evaluated for impairment				0	312
Collectively evaluated for impairment				728,777	717,796
Total ending loan balances				729,959	727,707
Commercial | Commercial real estate | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	112
Balance at end of year	5	112
Total ending allowance balance	112	112		5	112
Loans:
Total ending loan balances				1,182	9,599
Commercial | Multi-family
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	6,012	7,179
Charge-offs	0	0
Recoveries	169	3
Provision	5,195	(1,170)
Balance at end of year	11,376	6,012	7,179
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				11,376	6,012
Total ending allowance balance	6,012	7,179	7,179	11,376	6,012
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				1,365,262	904,300
Total ending loan balances				1,365,262	904,300
Commercial | Multi-family | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0	0
Total ending allowance balance	0	0		0	0
Loans:
Total ending loan balances				0	0
Commercial | SBA
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	683	335
Charge-offs	0	(106)
Recoveries	500	288
Provision	(244)	166
Balance at end of year	939	683	335
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				920	664
Total ending allowance balance	683	335	335	939	683
Loans:
Individually evaluated for impairment				0	3
Collectively evaluated for impairment				71,168	54,654
Total ending loan balances				73,840	57,706
Commercial | SBA | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	19
Balance at end of year	19	19
Total ending allowance balance	19	19		19	19
Loans:
Total ending loan balances				2,672	3,049
Commercial | Construction
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	1,530	846
Charge-offs	0	0
Recoveries	0	0
Provision	485	684
Balance at end of year	2,015	1,530	846
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				2,015	1,530
Total ending allowance balance	1,530	846	846	2,015	1,530
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				125,100	55,289
Total ending loan balances				125,100	55,289
Commercial | Construction | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0	0
Total ending allowance balance	0	0		0	0
Loans:
Total ending loan balances				0	0
Commercial | Lease financing
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	2,195	873
Charge-offs	(974)	(1,541)
Recoveries	283	79
Provision	(1,498)	2,784
Balance at end of year	6	2,195	873
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				6	2,195
Total ending allowance balance	2,195	873	873	6	2,195
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				379	192,424
Total ending loan balances				379	192,424
Commercial | Lease financing | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0	0
Total ending allowance balance	0	0		0	0
Loans:
Total ending loan balances				0	0
Consumer | Single Family Residential Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	13,854	7,192
Charge-offs	(1,057)	0
Recoveries	248	0
Provision	(970)	6,662
Balance at end of year	12,075	13,854	7,192
Individually evaluated for impairment				243	331
Collectively evaluated for impairment				11,752	13,506
Total ending allowance balance	13,854	7,192	7,192	12,075	13,854
Loans:
Individually evaluated for impairment				10,629	26,256
Collectively evaluated for impairment				1,962,789	1,530,098
Total ending loan balances				2,106,630	2,255,584
Consumer | Single Family Residential Mortgage | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	17
Balance at end of year	80	17
Total ending allowance balance	17	17		80	17
Loans:
Total ending loan balances				133,212	699,230
Consumer | Other Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	1,157	2,305
Charge-offs	(7)	(3)
Recoveries	26	16
Provision	(194)	(1,161)
Balance at end of year	982	1,157	2,305
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				982	1,157
Total ending allowance balance	1,157	2,305	$ 2,305	982	1,157
Loans:
Individually evaluated for impairment				294	553
Collectively evaluated for impairment				110,328	113,832
Total ending loan balances				110,622	114,385
Consumer | Other Consumer | PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0	0
Total ending allowance balance	$ 0	$ 0		0	0
Loans:
Total ending loan balances				$ 0	$ 0