PARENT COMPANY FINANCIALS ONLY (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net income	$ 9,968		$ 11,601	$ 8,874	$ 12,183	$ 11,169		$ 11,959	$ 11,120	$ 11,188	$ 42,627		$ 45,436		$ 40,240
Adjustments to reconcile net income to cash provided by operating activities
Deferred income tax benefit											(1,919)		91		(2,494)
Decrease in other assets											(4,380)		(32,482)		(15,608)
Increase (decrease) in other liabilities											4,408		14,871		13,894
Net cash provided by operating activities											41,684		55,531		46,653
Cash flows used in investing activities
Cash paid for acquisitions, net of cash acquired											(8,965)		(457)		(269)
Net cash used in investing activities											(265,671)		(189,828)		(163,784)
Cash flows provided by financing activities
Proceeds from stock issued and stock options exercised											1,108		4,127		743
Issuance of shares under direct stock purchase plan											1,691		824
Common Dividend Paid											(22,494)		(16,038)		(15,237)
Net cash provided by financing activities											201,957		210,519		156,508
Net (decrease) increase in cash and cash equivalents											(22,030)		76,222		39,377
Cash and cash equivalents at beginning of year					237,504					161,282	237,504		161,282		121,905
Cash and cash equivalents at end of year	215,474					237,504					215,474		237,504		161,282
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income											42,627		45,436		40,240
Adjustments to reconcile net income to cash provided by operating activities
Amortization											(13)		8		7
Deferred income tax benefit											(398)		(42)		(110)
Decrease in other assets											5,430
Increase (decrease) in other liabilities											(240)		(3,106)		1,480
Equity in undistributed income of subsidiaries											(16,000)		(26,812)		(23,807)
Net cash provided by operating activities											31,406		15,484		17,810
Cash flows used in investing activities
Cash paid for acquisitions, net of cash acquired											(21,648)
Net cash used in investing activities											(21,648)
Cash flows provided by financing activities
Proceeds from other borrowings											12,000
Repayment of other borrowings											(10,053)
Proceeds from stock issued and stock options exercised											1,242		4,127		743
Issuance of shares under direct stock purchase plan											1,691		824
Common Dividend Paid											(22,494)		(16,038)		(15,237)
Net cash provided by financing activities											(17,614)		(11,087)		(14,494)
Net (decrease) increase in cash and cash equivalents											(7,856)		4,397		3,316
Cash and cash equivalents at beginning of year					26,391					21,994	26,391		21,994		18,678
Cash and cash equivalents at end of year	18,535					26,391					18,535		26,391		21,994
Cash	$ 18,535	[1]				$ 26,391	[1]				$ 18,535	[1]	$ 26,391	[1]

[1] Entire balance eliminates in consolidation.