PARENT COMPANY FINANCIALS ONLY (Details 2) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income	$ 19,455		$ 18,594	$ 17,451	$ 9,460	$ 15,978	$ 15,738	$ 14,746	$ 13,383	$ 64,960		$ 59,845	$ 50,254
Adjustments to reconcile net income to net cash provided by operating activities
Deferred income tax expense										10,220		2,840	2,557
Change in other assets										3,812		(2,191)	48,903
Change in other liabilities										(2,276)		7,309	(16,016)
Net cash provided by operating activities										89,543		90,305	141,335
Cash flows used in investing activities
Net cash used in investing activities										(205,541)		(292,672)	(208,596)
Cash flows provided by financing activities
Net repayments of short-term Federal Home Loan Bank borrowings										(10,000)		(65,000)	(50,000)
Restricted stock awards issued, net of awards surrendered										(657)		(641)	(669)
Proceeds from stock issued and stock options exercised										1,367		2,333	2,475
Proceeds from shares issued under the direct stock purchase plan										2,695		1,555	969
Common dividends paid										(26,172)		(22,443)	(15,122)
Net cash provided by financing activities										213,509		164,296	68,112
Net increase (decrease) in cash and cash equivalents										97,511		(38,071)	851
Cash and cash equivalents at beginning of year					178,254				216,325	178,254		216,325	215,474
Cash and cash equivalents at end of period	275,765					178,254				275,765		178,254	216,325
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income										64,960		59,845	50,254
Adjustments to reconcile net income to net cash provided by operating activities
Accretion										(150)		(486)	(155)
Deferred income tax expense										3,266		293	203
Change in other assets										7,314			(373)
Change in other liabilities										(80)		25	206
Equity in undistributed income of subsidiaries										(30,226)		(22,545)	(22,305)
Net cash provided by operating activities										45,084		37,132	27,830
Cash flows used in investing activities
Cash paid for acquisitions, net of cash acquired										(51,680)			(10,832)
Net cash used in investing activities										(51,680)			(10,832)
Cash flows provided by financing activities
Proceeds from short-term borrowings													10,000
Repayment of short-term borrowings												(5,000)	(17,000)
Net repayments of short-term Federal Home Loan Bank borrowings												35,000
Restricted stock awards issued, net of awards surrendered										(657)		(641)	0
Proceeds from stock issued and stock options exercised										1,367		2,333	2,475
Proceeds from shares issued under the direct stock purchase plan										2,695		1,555	969
Common dividends paid										(26,172)		(22,443)	(15,122)
Net cash provided by financing activities										(22,767)		10,804	(18,678)
Net increase (decrease) in cash and cash equivalents										(29,363)		47,936	(1,680)
Cash and cash equivalents at beginning of year					$ 64,791				$ 16,855	64,791		16,855	18,535
Cash and cash equivalents at end of period	35,428					64,791				35,428		64,791	$ 16,855
Cash	$ 35,428	[1]				$ 64,791				$ 35,428	[1]	$ 64,791

[1] Entire balance eliminates in consolidation.