The aggregate total of expenses of managing and administering the affairs of the entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line and the indirect expenses and costs incurred during the reporting period.

No definition available.

SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended								12 Months Ended
SEGMENT INFORMATION (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment									3
SEGMENT INFORMATION
Net interest income (expense)	$ 44,679	$ 43,325	$ 42,672	$ 42,322	$ 42,824	$ 41,995	$ 41,629	$ 41,255	$ 172,998	$ 167,703	$ 157,950
Credit (provision) for loan and lease losses	1,386	59	(532)	211	186	126	2,282	80	1,124	2,674	5,517
Other operating income									38,804	36,496	42,316
Other operating expense									(134,682)	(131,073)	(132,518)
Administrative and overhead expense allocation									0	0	0
Income before income taxes	21,823	20,179	18,159	18,083	17,656	18,353	19,669	20,122	78,244	75,800	73,265
Income taxes									(18,758)	(34,596)	(26,273)
Net income	15,792	$ 15,193	$ 14,224	$ 14,277	4,288	$ 11,812	$ 12,025	$ 13,079	59,486	41,204	46,992
Investment securities	1,354,812				1,496,644				1,354,812	1,496,644
Loans and leases (including loans held for sale)	4,085,013				3,786,951				4,085,013	3,786,951
Other	367,201				340,113				367,201	340,113
Total assets	5,807,026				5,623,708				5,807,026	5,623,708
Banking Operations
SEGMENT INFORMATION
Net interest income (expense)									153,314	140,077	128,673
Credit (provision) for loan and lease losses									1,124	2,674	5,517
Other operating income									23,879	22,511	25,994
Other operating expense									(63,649)	(60,939)	(58,856)
Administrative and overhead expense allocation									(60,636)	(61,082)	(64,139)
Income taxes									(19,832)	(34,376)	(25,796)
Net income									62,891	41,842	48,048
Investment securities	0				0				0	0
Loans and leases (including loans held for sale)	4,085,013				3,786,951				4,085,013	3,786,951
Other	36,905				42,243				36,905	42,243
Total assets	4,121,918				3,829,194				4,121,918	3,829,194
Treasury
SEGMENT INFORMATION
Net interest income (expense)									19,684	27,626	29,277
Credit (provision) for loan and lease losses									0	0	0
Other operating income									2,733	2,448	3,148
Other operating expense									(1,472)	(1,433)	(1,616)
Administrative and overhead expense allocation									(874)	(972)	(918)
Income taxes									(428)	(1,204)	(1,143)
Net income									1,359	1,465	2,130
Investment securities	1,354,812				1,496,644				1,354,812	1,496,644
Loans and leases (including loans held for sale)	0				0				0	0
Other	256,652				228,608				256,652	228,608
Total assets	1,611,464				1,725,252				1,611,464	1,725,252
All Others
SEGMENT INFORMATION
Net interest income (expense)									0	0	0
Credit (provision) for loan and lease losses									0	0	0
Other operating income									12,192	11,537	13,174
Other operating expense									(69,561)	(68,701)	(72,046)
Administrative and overhead expense allocation									61,510	62,054	65,057
Income taxes									1,502	984	666
Net income									(4,764)	(2,103)	(3,186)
Investment securities	0				0				0	0
Loans and leases (including loans held for sale)	0				0				0	0
Other	73,644				69,262				73,644	69,262
Total assets	$ 73,644				$ 69,262				73,644	69,262
Intersegment elimination
SEGMENT INFORMATION
Net interest income (expense)									0	0	0
Intersegment elimination \| Banking Operations
SEGMENT INFORMATION
Net interest income (expense)									28,691	32,977	36,655
Intersegment elimination \| Treasury
SEGMENT INFORMATION
Net interest income (expense)									(18,284)	(25,000)	(26,618)
Intersegment elimination \| All Others
SEGMENT INFORMATION
Net interest income (expense)									(10,407)	(7,977)	(10,037)
Operating Segments [Member]
SEGMENT INFORMATION
Income before income taxes									78,244	75,800	73,265
Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Income before income taxes									82,723	76,218	73,844
Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Income before income taxes									1,787	2,669	3,273
Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Income before income taxes									(6,266)	$ (3,087)	$ (3,852)
Service charges on deposit accounts \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									8,406
Service charges on deposit accounts \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									8,406
Service charges on deposit accounts \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									0
Service charges on deposit accounts \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Other service charges and fees \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									13,123
Other service charges and fees \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									5,154
Other service charges and fees \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									23
Other service charges and fees \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									7,946
Income from fiduciary activities \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									4,245
Income from fiduciary activities \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									4,245
Income from fiduciary activities \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									0
Income from fiduciary activities \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Equity in Earnings of Unconsolidated Subsidiaries [Member] \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									233
Equity in Earnings of Unconsolidated Subsidiaries [Member] \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									233
Equity in Earnings of Unconsolidated Subsidiaries [Member] \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									0
Equity in Earnings of Unconsolidated Subsidiaries [Member] \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Fees on foreign exchange \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									905
Fees on foreign exchange \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									98
Fees on foreign exchange \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									807
Fees on foreign exchange \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Investment Securities Gains (Losses) [Member] \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									(279)
Investment Securities Gains (Losses) [Member] \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									0
Investment Securities Gains (Losses) [Member] \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									(279)
Investment Securities Gains (Losses) [Member] \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Income from Bank-owned Life Insurance [Member] \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									2,117
Income from Bank-owned Life Insurance [Member] \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									0
Income from Bank-owned Life Insurance [Member] \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									2,117
Income from Bank-owned Life Insurance [Member] \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Loan placement fees \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									747
Loan placement fees \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									747
Loan placement fees \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									0
Loan placement fees \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									0
Other [Member] \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									1,992
Other [Member] \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									981
Other [Member] \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									65
Other [Member] \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									946
Mortgage Banking Income [Member] \| Operating Segments [Member]
SEGMENT INFORMATION
Other operating income									7,315
Mortgage Banking Income [Member] \| Operating Segments [Member] \| Banking Operations
SEGMENT INFORMATION
Other operating income									4,015
Mortgage Banking Income [Member] \| Operating Segments [Member] \| Treasury
SEGMENT INFORMATION
Other operating income									0
Mortgage Banking Income [Member] \| Operating Segments [Member] \| All Others
SEGMENT INFORMATION
Other operating income									$ 3,300