SEGMENT REPORTING (Operating Segments and Reconciliation of Information to Condensed Consolidated Financial Statements) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Interest income	$ 41,803	$ 38,849	$ 83,456	$ 76,921
Interest expense	5,071	4,916	10,602	9,615
Provision (credit)	2,957	1,218	4,193	1,815	$ 5,371
Non-interest income	12,751	12,109	26,114	25,268
Non-interest Expense	30,871	29,477	63,188	58,721
Income before income taxes	15,655	15,347	31,587	32,038
Income tax expense	5,008	5,014	10,127	10,480
Net income	10,647	10,333	21,460	21,558
Assets	4,739,449	4,507,367	4,739,449	4,507,367	$ 4,655,380
Intersegment Elimination
Segment Reporting Information [Line Items]
Interest income	(2)	(2)	(4)	(3)
Interest expense	(2)	(2)	(4)	(3)
Provision (credit)	0	0	0	0
Non-interest income	(178)	(15,574)	(356)	(15,755)
Non-interest Expense	(178)	(15,574)	(356)	(15,755)
Income before income taxes	0	0	0	0
Income tax expense	0	0	0	0
Net income	0	0	0	0
Assets	(20,274)	(17,810)	(20,274)	(17,810)
Community Banking
Segment Reporting Information [Line Items]
Interest income	41,804	38,849	83,457	76,920
Interest expense	5,073	4,918	10,606	9,618
Provision (credit)	2,957	1,218	4,193	1,815
Non-interest income	10,136	24,945	20,355	34,781
Non-interest Expense	28,999	42,958	59,379	69,975
Income before income taxes	14,911	14,700	29,634	30,293
Income tax expense	4,718	4,763	9,362	9,797
Net income	10,193	9,937	20,272	20,496
Assets	4,742,368	4,508,858	4,742,368	4,508,858
Insurance
Segment Reporting Information [Line Items]
Interest income	0	0	1	1
Interest expense	0	0	0	0
Provision (credit)	0	0	0	0
Non-interest income	950	984	2,403	2,678
Non-interest Expense	1,030	1,169	2,201	2,552
Income before income taxes	(80)	(185)	203	127
Income tax expense	(31)	(74)	83	52
Net income	(49)	(111)	120	75
Assets	5,754	5,647	5,754	5,647
Investment Management
Segment Reporting Information [Line Items]
Interest income	1	2	2	3
Interest expense	0	0	0	0
Provision (credit)	0	0	0	0
Non-interest income	1,843	1,754	3,712	3,564
Non-interest Expense	1,020	924	1,964	1,949
Income before income taxes	824	832	1,750	1,618
Income tax expense	321	325	682	631
Net income	503	507	1,068	987
Assets	$ 11,601	$ 10,672	$ 11,601	$ 10,672