Investment Securities (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013 Security		Jun. 30, 2012		Jun. 30, 2013 Security		Jun. 30, 2012		Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 478,813,000		$ 488,919,000		$ 478,813,000		$ 488,919,000		$ 405,914,000
Gross Unrealized Gains	4,708,000		12,990,000		4,708,000		12,990,000		12,099,000
Gross Unrealized Losses	8,107,000		17,000		8,107,000		17,000		22,000
Fair/Book Value, Total	475,414,000		501,892,000		475,414,000		501,892,000		417,991,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	235,960,000		3,405,000		235,960,000		3,405,000		7,984,000
12 Months or More Fair Value	0		0		0		0		0
Total Fair Value	235,960,000		3,405,000		235,960,000		3,405,000		7,984,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	8,107,000		17,000		8,107,000		17,000		22,000
12 Months or More Unrealized Loss	0		0		0		0		0
Total Unrealized Loss	8,107,000		17,000		8,107,000		17,000		22,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	67,059,000		70,195,000		67,059,000		70,195,000		68,392,000
Gross Unrealized Gains	1,255,000		2,523,000		1,255,000		2,523,000		2,308,000
Gross Unrealized Losses	531,000		51,000		531,000		51,000		3,000
Fair Value	67,783,000		72,667,000		67,783,000		72,667,000		70,697,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less than Twelve Months Fair Value	9,626,000		4,774,000		9,626,000		4,774,000		528,000
Twelve Months or More Fair Value	0		0		0		0		0
Total Fair Value	9,626,000		4,774,000		9,626,000		4,774,000		528,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less than 12 Months Unrealized Loss	531,000		51,000		531,000		51,000		3,000
12 Months or Longer Unrealized Loss	0		0		0		0		0
Total Unrealized Loss	531,000		51,000		531,000		51,000		3,000
Amortized Cost [Abstract]
Within one year	11,680,000				11,680,000
After one year through five years	64,383,000				64,383,000
After five years through ten years	1,310,000				1,310,000
After ten years	5,399,000				5,399,000
Amortized cost, before single maturity date	82,772,000				82,772,000
Investment securities not due at a single maturity date - Mortgage-backed securities	396,041,000				396,041,000
Amortized cost, Total	478,813,000				478,813,000
Fair/Book Value [Abstract]
Within one year	11,718,000				11,718,000
After one year through five years	64,378,000				64,378,000
After five years through ten years	1,345,000				1,345,000
After ten years	5,399,000				5,399,000
Fair/Book Value, before single maturity date	82,840,000				82,840,000
Investment securities not due at a single maturity date - Mortgage-backed securities	392,574,000				392,574,000
Fair/Book Value, Total	475,414,000		501,892,000		475,414,000		501,892,000		417,991,000
Amortized Cost [Abstract]
Within one year	2,075,000				2,075,000
After one year through five years	13,317,000				13,317,000
After five years through ten years	36,228,000				36,228,000
After ten years	15,222,000				15,222,000
Amortized cost, before single maturity date	66,842,000				66,842,000
Investment securities not due at a single maturity date - Mortgage-backed securities	217,000				217,000
Amortized cost, Total	67,059,000				67,059,000
Fair Value [Abstract]
Within one year	2,084,000				2,084,000
After one year through five years	13,627,000				13,627,000
After five years through ten years	37,161,000				37,161,000
After ten years	14,691,000				14,691,000
Fair/Book Value, before single maturity date	67,563,000				67,563,000
Investment securities not due at a single maturity date - Mortgage-backed securities	220,000				220,000
Fair/Book Value, Total	67,783,000				67,783,000
Proceeds from sales of securities available-for-sale [Abstract]
Proceeds	4,356,000		1,530,000		49,615,000		26,530,000
Gains	154,000		0		903,000		0
Losses	0		0		14,000		0
Gain (Loss) on Investments [Line Items]
Number of investment securities held	363				363
Number of loss positions less than twelve months					82
Number of loss positions in twelve months or more					0
Percentage of bank qualified municipal bond portfolio rated (in hundredths)					94.00%
Percentage of portfolio not rated (in hundredths)					6.00%
Securities pledged to secure public deposits, FHLB borrowings, and other government agency deposits as required by law	290,600,000				290,600,000				296,900,000
Government Agency Government Sponsored Entities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	0		0		0		0		0
Mortgage Backed Securities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	7,800,000		0		7,800,000		0		10,000
Obligations of States and Political Subdivisions [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	531,000		51,000		531,000		51,000		3,000
Corporate Securities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	267,000		17,000		267,000		17,000		12,000
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	64,648,000		67,159,000		64,648,000		67,159,000		65,694,000
Gross Unrealized Gains	1,252,000		2,498,000		1,252,000		2,498,000		2,296,000
Gross Unrealized Losses	531,000		51,000		531,000		51,000		3,000
Fair Value	65,369,000		69,606,000		65,369,000		69,606,000		67,987,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less than Twelve Months Fair Value	9,626,000		4,774,000		9,626,000		4,774,000		528,000
Twelve Months or More Fair Value	0		0		0		0		0
Total Fair Value	9,626,000		4,774,000		9,626,000		4,774,000		528,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less than 12 Months Unrealized Loss	531,000		51,000		531,000		51,000		3,000
12 Months or Longer Unrealized Loss	0		0		0		0		0
Total Unrealized Loss	531,000		51,000		531,000		51,000		3,000
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	217,000	[1]	806,000	[1]	217,000	[1]	806,000	[1]	484,000	[1]
Gross Unrealized Gains	3,000	[1]	25,000	[1]	3,000	[1]	25,000	[1]	12,000	[1]
Gross Unrealized Losses	0	[1]	0	[1]	0	[1]	0	[1]	0	[1]
Fair Value	220,000	[1]	831,000	[1]	220,000	[1]	831,000	[1]	496,000	[1]
Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	2,194,000		2,230,000		2,194,000		2,230,000		2,214,000
Gross Unrealized Gains	0		0		0		0		0
Gross Unrealized Losses	0		0		0		0		0
Fair Value	2,194,000		2,230,000		2,194,000		2,230,000		2,214,000
Government Agency & Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,327,000		56,764,000		26,327,000		56,764,000		26,546,000
Gross Unrealized Gains	155,000		314,000		155,000		314,000		277,000
Gross Unrealized Losses	0		0		0		0		0
Fair/Book Value, Total	26,482,000		57,078,000		26,482,000		57,078,000		26,823,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	26,482,000		57,078,000		26,482,000		57,078,000		26,823,000
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,612,000		5,724,000		5,612,000		5,724,000		5,665,000
Gross Unrealized Gains	0		0		0		0		0
Gross Unrealized Losses	0		0		0		0		0
Fair/Book Value, Total	5,612,000		5,724,000		5,612,000		5,724,000		5,665,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	5,612,000		5,724,000		5,612,000		5,724,000		5,665,000
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	396,041,000	[1]	414,990,000	[1]	396,041,000	[1]	414,990,000	[1]	341,212,000	[1]
Gross Unrealized Gains	4,373,000	[1]	12,647,000	[1]	4,373,000	[1]	12,647,000	[1]	11,570,000	[1]
Gross Unrealized Losses	7,840,000	[1]	0	[1]	7,840,000	[1]	0	[1]	10,000	[1]
Fair/Book Value, Total	392,574,000	[1]	427,637,000	[1]	392,574,000	[1]	427,637,000	[1]	352,772,000	[1]
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	205,363,000				205,363,000				4,542,000
12 Months or More Fair Value	0				0				0
Total Fair Value	205,363,000				205,363,000				4,542,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	7,840,000				7,840,000				10,000
12 Months or More Unrealized Loss	0				0				0
Total Unrealized Loss	7,840,000				7,840,000				10,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	392,574,000	[1]	427,637,000	[1]	392,574,000	[1]	427,637,000	[1]	352,772,000	[1]
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	49,647,000		8,983,000		49,647,000		8,983,000		22,318,000
Gross Unrealized Gains	180,000		29,000		180,000		29,000		252,000
Gross Unrealized Losses	267,000		17,000		267,000		17,000		12,000
Fair/Book Value, Total	49,560,000		8,995,000		49,560,000		8,995,000		22,558,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	30,597,000		3,405,000		30,597,000		3,405,000		3,442,000
12 Months or More Fair Value	0		0		0		0		0
Total Fair Value	30,597,000		3,405,000		30,597,000		3,405,000		3,442,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	267,000		17,000		267,000		17,000		12,000
12 Months or More Unrealized Loss	0		0		0		0		0
Total Unrealized Loss	267,000		17,000		267,000		17,000		12,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	49,560,000		8,995,000		49,560,000		8,995,000		22,558,000
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,186,000		2,458,000		1,186,000		2,458,000		10,173,000
Gross Unrealized Gains	0		0		0		0		0
Gross Unrealized Losses	0		0		0		0		0
Fair/Book Value, Total	1,186,000		2,458,000		1,186,000		2,458,000		10,173,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	$ 1,186,000		$ 2,458,000		$ 1,186,000		$ 2,458,000		$ 10,173,000

[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.