SECURITIES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013 item	Jun. 30, 2012	Mar. 31, 2012 item	Jun. 30, 2013 item	Jun. 30, 2012	Dec. 31, 2012
Available for sale securities
Amortized Cost	$ 875,486			$ 875,486		$ 862,759
Gross Unrealized Gains	21,057			21,057		39,837
Gross Unrealized Losses	(9,635)			(9,635)		(255)
Fair Value	886,908			886,908		902,341
Available for Sale, Amortized Cost
Within one year	12,002			12,002
One through five years	54,074			54,074
Six through ten years	104,320			104,320
After ten years	150,838			150,838
Equity securities	4,939			4,939
Total available for sale securities	875,486			875,486		862,759
Available for Sale, Fair Value
Within one year	12,221			12,221
One through five years	56,210			56,210
Six through ten years	108,391			108,391
After ten years	158,006			158,006
Equity securities	4,939			4,939
Fair Value	886,908			886,908		902,341
Available for sale securities
Proceeds from sales of securities	964	930		78,354	20,886
Gross gains realized on sales	11	48		910	1,070
Gross losses realized on sales	22	0		77	35
Number of investments on which impairment loss was recognized			1
Impairment loss recognized			500
Cost basis of one of the equity holdings			250
Securities in a continuous unrealized loss position with unrealized losses presented by length of time
Less than 12 months, Fair Value	312,884			312,884		52,732
Less than 12 months, Unrealized Losses	(9,635)			(9,635)		(255)
Total Fair Value	312,884			312,884		52,732
Total Unrealized Losses	(9,635)			(9,635)		(255)
Other-Than-Temporary-Impairment
Number of general segments segregated in investment securities portfolio				2
Number of securities in the portfolio				1,016
Number of portfolio securities in unrealized loss position	143			143
U. S. government agency
Available for sale securities
Amortized Cost	1,117			1,117		1,600
Gross Unrealized Gains	16			16		38
Fair Value	1,133			1,133		1,638
Available for Sale, Amortized Cost
Total available for sale securities	1,117			1,117		1,600
Available for Sale, Fair Value
Fair Value	1,133			1,133		1,638
State and municipal
Available for sale securities
Amortized Cost	316,574			316,574		310,552
Gross Unrealized Gains	15,311			15,311		27,484
Gross Unrealized Losses	(1,722)			(1,722)		(97)
Fair Value	330,163			330,163		337,939
Available for Sale, Amortized Cost
Total available for sale securities	316,574			316,574		310,552
Available for Sale, Fair Value
Fair Value	330,163			330,163		337,939
Securities in a continuous unrealized loss position with unrealized losses presented by length of time
Less than 12 months, Fair Value	29,662			29,662		6,646
Less than 12 months, Unrealized Losses	(1,722)			(1,722)		(97)
Total Fair Value	29,662			29,662		6,646
Total Unrealized Losses	(1,722)			(1,722)		(97)
Mortgage-backed securities-residential (Government Sponsored Entity)
Available for sale securities
Amortized Cost	196,151			196,151		219,352
Gross Unrealized Gains	3,633			3,633		7,711
Gross Unrealized Losses	(2,822)			(2,822)		(8)
Fair Value	196,962			196,962		227,055
Available for Sale, Amortized Cost
Debt securities without single maturity date	196,151			196,151
Total available for sale securities	196,151			196,151		219,352
Available for Sale, Fair Value
Debt securities without single maturity date	196,962			196,962
Fair Value	196,962			196,962		227,055
Securities in a continuous unrealized loss position with unrealized losses presented by length of time
Less than 12 months, Fair Value	91,405			91,405		12,766
Less than 12 months, Unrealized Losses	(2,822)			(2,822)		(8)
Total Fair Value	91,405			91,405		12,766
Total Unrealized Losses	(2,822)			(2,822)		(8)
Collateralized mortgage obligations (Government Sponsored Entity)
Available for sale securities
Amortized Cost	353,162			353,162		322,758
Gross Unrealized Gains	2,097			2,097		4,604
Gross Unrealized Losses	(5,080)			(5,080)		(139)
Fair Value	350,179			350,179		327,223
Available for Sale, Amortized Cost
Debt securities without single maturity date	353,162			353,162
Total available for sale securities	353,162			353,162		322,758
Available for Sale, Fair Value
Debt securities without single maturity date	350,179			350,179
Fair Value	350,179			350,179		327,223
Securities in a continuous unrealized loss position with unrealized losses presented by length of time
Less than 12 months, Fair Value	190,827			190,827		32,330
Less than 12 months, Unrealized Losses	(5,080)			(5,080)		(139)
Total Fair Value	190,827			190,827		32,330
Total Unrealized Losses	(5,080)			(5,080)		(139)
Other-Than-Temporary-Impairment
Other than temporary impairment				0
Equity securities
Available for sale securities
Amortized Cost	4,939			4,939		4,939
Fair Value	4,939			4,939		4,939
Available for Sale, Amortized Cost
Total available for sale securities	4,939			4,939		4,939
Available for Sale, Fair Value
Fair Value	4,939			4,939		4,939
Other securities
Available for sale securities
Amortized Cost	3,543			3,543		3,558
Gross Unrealized Losses	(11)			(11)		(11)
Fair Value	3,532			3,532		3,547
Available for Sale, Amortized Cost
Total available for sale securities	3,543			3,543		3,558
Available for Sale, Fair Value
Fair Value	3,532			3,532		3,547
Securities in a continuous unrealized loss position with unrealized losses presented by length of time
Less than 12 months, Fair Value	990			990		990
Less than 12 months, Unrealized Losses	(11)			(11)		(11)
Total Fair Value	990			990		990
Total Unrealized Losses	$ (11)			$ (11)		$ (11)
Other-Than-Temporary-Impairment
Number of single issue trust preferred securities to which the unrealized losses on other securities are related				1