Investment Securities (Details) (USD $)	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 447,408,000		$ 411,409,000		$ 471,767,000
Gross Unrealized Gains	15,769,000		9,422,000		8,205,000
Gross Unrealized Losses	0		22,000		152,000
Total Assets Measured at Fair Value On a Recurring Basis	463,177,000		420,809,000		479,820,000
Less Than 12 Months [Abstract]
Fair Value			10,130,000		90,077,000
Unrealized Loss			22,000		152,000
12 Months or More [Abstract]
Fair Value			0		0
Unrealized Loss			0		0
Total [Abstract]
Fair Value			10,130,000		90,077,000
Unrealized Loss			22,000		152,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	68,960,000		63,803,000		63,092,000
Gross Unrealized Gains	2,643,000		2,499,000		2,782,000
Gross Unrealized Losses	0		0		0
Fair Value	71,603,000		66,302,000		65,874,000
Securities available-for-sale [Abstract]
Within 1 Year	16,440,000
After 1 but Within 5	49,162,000
After 5 but Within 10	121,297,000
Over 10 years	276,278,000
Total Assets Measured at Fair Value On a Recurring Basis	463,177,000		420,809,000		479,820,000
Held-to-maturity securities [Abstract]
Within 1 Year	1,540,000
After 1 but Within 5	10,487,000
After 5 but Within 10	41,569,000
Over 10 years	15,364,000
Total Book Value	68,960,000		63,803,000		63,092,000
Proceeds from calls of securities [Abstract]
Proceeds from calls of securities	44,296,000		55,000,000
Gains from calls of securities	149,000		0
Realized losses from call of securities	0		0
Number of investment securities held	360
Number of loss positions less than twelve months	0
Number of loss positions in twelve months or more	0
Percentage of bank qualified municipal bond portfolio rated (in hundredths)	93.00%
Percentage of portfolio not rated (in hundredths)	7.00%
Securities pledged to secure public deposits, FHLB borrowings, and other government agency deposits as required by law	307,200,000		382,900,000		373,200,000
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	66,098,000		60,130,000		59,640,000
Gross Unrealized Gains	2,623,000		2,437,000		2,736,000
Gross Unrealized Losses	0		0		0
Fair Value	68,721,000		62,567,000		62,376,000
Held-to-maturity securities [Abstract]
Total Book Value	66,098,000		60,130,000		59,640,000
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	640,000	[1]	1,418,000	[1]	1,205,000	[1]
Gross Unrealized Gains	20,000	[1]	62,000	[1]	46,000	[1]
Gross Unrealized Losses	0	[1]	0	[1]	0	[1]
Fair Value	660,000	[1]	1,480,000	[1]	1,251,000	[1]
Held-to-maturity securities [Abstract]
Total Book Value	640,000	[1]	1,418,000	[1]	1,205,000	[1]
Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	2,222,000		2,255,000		2,247,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Fair Value	2,222,000		2,255,000		2,247,000
Held-to-maturity securities [Abstract]
Total Book Value	2,222,000		2,255,000		2,247,000
Government Agency & Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	46,655,000		162,115,000		82,195,000
Gross Unrealized Gains	316,000		635,000		413,000
Gross Unrealized Losses	0		0		13,000
Total Assets Measured at Fair Value On a Recurring Basis	46,971,000		162,750,000		82,595,000
Less Than 12 Months [Abstract]
Fair Value					4,987,000
Unrealized Loss	0		0		13,000
12 Months or More [Abstract]
Fair Value					0
Unrealized Loss	0		0		0
Total [Abstract]
Fair Value					4,987,000
Unrealized Loss	0		0		13,000
Securities available-for-sale [Abstract]
Within 1 Year	10,006,000
After 1 but Within 5	35,751,000
After 5 but Within 10	1,214,000
Over 10 years	0
Total Assets Measured at Fair Value On a Recurring Basis	46,971,000		162,750,000		82,595,000
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,704,000		5,813,000		5,782,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Total Assets Measured at Fair Value On a Recurring Basis	5,704,000		5,813,000		5,782,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	66,098,000
Securities available-for-sale [Abstract]
Within 1 Year	0
After 1 but Within 5	0
After 5 but Within 10	219,000
Over 10 years	5,485,000
Total Assets Measured at Fair Value On a Recurring Basis	5,704,000		5,813,000		5,782,000
Held-to-maturity securities [Abstract]
Within 1 Year	1,540,000
After 1 but Within 5	9,842,000
After 5 but Within 10	39,352,000
Over 10 years	15,364,000
Total Book Value	66,098,000
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	374,582,000	[1]	243,121,000	[1]	383,380,000	[1]
Gross Unrealized Gains	15,230,000	[1]	8,787,000	[1]	7,792,000	[1]
Gross Unrealized Losses	0	[1]	22,000	[1]	139,000	[1]
Total Assets Measured at Fair Value On a Recurring Basis	389,812,000	[1]	251,886,000	[1]	391,033,000	[1]
Less Than 12 Months [Abstract]
Fair Value			10,130,000		85,090,000
Unrealized Loss	0		22,000		139,000
12 Months or More [Abstract]
Fair Value			0		0
Unrealized Loss	0		0		0
Total [Abstract]
Fair Value			10,130,000		85,090,000
Unrealized Loss	0		22,000		139,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	640,000
Securities available-for-sale [Abstract]
Within 1 Year	0
After 1 but Within 5	0
After 5 but Within 10	119,019,000
Over 10 years	270,793,000
Total Assets Measured at Fair Value On a Recurring Basis	389,812,000	[1]	251,886,000	[1]	391,033,000	[1]
Held-to-maturity securities [Abstract]
Within 1 Year	0
After 1 but Within 5	640,000
After 5 but Within 10	0
Over 10 years	0
Total Book Value	640,000
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,641,000
Gross Unrealized Gains	223,000
Gross Unrealized Losses	0
Total Assets Measured at Fair Value On a Recurring Basis	14,864,000
Securities available-for-sale [Abstract]
Within 1 Year	608,000
After 1 but Within 5	13,411,000
After 5 but Within 10	845,000
Over 10 years	0
Total Assets Measured at Fair Value On a Recurring Basis	14,864,000
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,826,000		360,000		410,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Total Assets Measured at Fair Value On a Recurring Basis	5,826,000		360,000		410,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	2,222,000
Securities available-for-sale [Abstract]
Within 1 Year	5,826,000
After 1 but Within 5	0
After 5 but Within 10	0
Over 10 years	0
Total Assets Measured at Fair Value On a Recurring Basis	5,826,000		360,000		410,000
Held-to-maturity securities [Abstract]
Within 1 Year	0
After 1 but Within 5	5,000
After 5 but Within 10	2,217,000
Over 10 years	0
Total Book Value	$ 2,222,000

[1] All Mortgage Backed Securities consist of securities collateralized by residential real estate and were issued by an agency or government sponsored entity of the U.S. government.