Investment Securities (Details) (USD $)	3 Months Ended
	Mar. 31, 2013 Security		Mar. 31, 2012		Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 506,048,000		$ 522,381,000		$ 405,914,000
Gross Unrealized Gains	10,850,000		9,694,000		12,099,000
Gross Unrealized Losses	1,325,000		258,000		22,000
Fair/Book Value, Total	515,573,000		531,817,000		417,991,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	133,929,000		56,721,000		7,984,000
12 Months or More Fair Value	0		0		0
Total Fair Value	133,929,000		56,721,000		7,984,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	1,325,000		258,000		22,000
12 Months or More Unrealized Loss	0		0		0
Total Unrealized Loss	1,325,000		258,000		22,000
Schedule of Held-to-maturity Securities [Line Items]
Book Value	67,708,000		66,416,000		68,392,000
Gross Unrealized Gains	1,904,000		2,602,000		2,308,000
Gross Unrealized Losses	22,000		0		3,000
Fair Value	69,590,000		69,018,000		70,697,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less than Twelve Months Fair Value	2,841,000				528,000
Twelve Months or More Fair Value	0				0
Total Fair Value	2,841,000				528,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less than 12 Months Unrealized Loss	22,000				3,000
12 Months or Longer Unrealized Loss	0				0
Total Unrealized Loss	22,000				3,000
Amortized Cost [Abstract]
Within one year	11,424,000
After one year through five years	64,583,000
After five years through ten years	1,315,000
After ten years	5,428,000
Amortized cost, before single maturity date	82,750,000
Investment securities not due at a single maturity date - Mortgage-backed securities	423,298,000
Amortized cost, Total	506,048,000
Fair/Book Value [Abstract]
Within one year	11,475,000
After one year through five years	64,968,000
After five years through ten years	1,417,000
After ten years	5,428,000
Fair/Book Value, before single maturity date	83,288,000
Investment securities not due at a single maturity date - Mortgage-backed securities	432,285,000
Fair/Book Value, Total	515,573,000		531,817,000		417,991,000
Amortized Cost [Abstract]
Within one year	1,775,000
After one year through five years	12,144,000
After five years through ten years	38,182,000
After ten years	15,266,000
Amortized cost, before single maturity date	67,367,000
Investment securities not due at a single maturity date - Mortgage-backed securities	341,000
Amortized cost, Total	67,708,000
Fair Value [Abstract]
Within one year	1,788,000
After one year through five years	12,527,000
After five years through ten years	39,602,000
After ten years	15,324,000
Fair/Book Value, before single maturity date	69,241,000
Investment securities not due at a single maturity date - Mortgage-backed securities	349,000
Fair/Book Value, Total	69,590,000
Proceeds from sales of securities available-for-sale [Abstract]
Proceeds from sales and calls of securities	45,259,000		25,000,000
Realized gains from sales and calls	749,000		0
Realized losses from sales and calls	14,000		0
Gain (Loss) on Investments [Line Items]
Number of investment securities held	355
Number of loss positions less than twelve months	27
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	300,200,000				296,900,000
Government Agency Government Sponsored Entities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	0		0		0
Mortgage Backed Securities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	1,300,000		258,000		10,000
Obligations of States and Political Subdivisions [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	22,000		0		3,000
Corporate Securities [Member]
Gain (Loss) on Investments [Line Items]
Unrealized losses	39,000		0		12,000
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	65,165,000		63,174,000		65,694,000
Gross Unrealized Gains	1,896,000		2,565,000		2,296,000
Gross Unrealized Losses	22,000		0		3,000
Fair Value	67,039,000		65,739,000		67,987,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less than Twelve Months Fair Value	2,841,000				528,000
Twelve Months or More Fair Value	0				0
Total Fair Value	2,841,000				528,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less than 12 Months Unrealized Loss	22,000				3,000
12 Months or Longer Unrealized Loss	0				0
Total Unrealized Loss	22,000				3,000
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	341,000	[1]	1,003,000	[1]	484,000	[1]
Gross Unrealized Gains	8,000	[1]	37,000	[1]	12,000	[1]
Gross Unrealized Losses	0	[1]	0	[1]	0	[1]
Fair Value	349,000	[1]	1,040,000	[1]	496,000	[1]
Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Book Value	2,202,000		2,239,000		2,214,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Fair Value	2,202,000		2,239,000		2,214,000
Government Agency & Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,436,000		66,995,000		26,546,000
Gross Unrealized Gains	256,000		347,000		277,000
Gross Unrealized Losses	0		0		0
Fair/Book Value, Total	26,692,000		67,342,000		26,823,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	26,692,000		67,342,000		26,823,000
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,643,000		5,753,000		5,665,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Fair/Book Value, Total	5,643,000		5,753,000		5,665,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	5,643,000		5,753,000		5,665,000
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	423,298,000	[1]	439,222,000	[1]	341,212,000	[1]
Gross Unrealized Gains	10,273,000	[1]	9,347,000	[1]	11,570,000	[1]
Gross Unrealized Losses	1,286,000	[1]	258,000	[1]	10,000	[1]
Fair/Book Value, Total	432,285,000	[1]	448,311,000	[1]	352,772,000	[1]
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	115,238,000		56,721,000		4,542,000
12 Months or More Fair Value	0		0		0
Total Fair Value	115,238,000		56,721,000		4,542,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	1,286,000		258,000		10,000
12 Months or More Unrealized Loss	0		0		0
Total Unrealized Loss	1,286,000		258,000		10,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	432,285,000	[1]	448,311,000	[1]	352,772,000	[1]
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	49,846,000		344,000		22,318,000
Gross Unrealized Gains	321,000		0		252,000
Gross Unrealized Losses	39,000		0		12,000
Fair/Book Value, Total	50,128,000		344,000		22,558,000
Individual securities in continuous unrealized loss position, fair value [Abstract]
Less Than 12 Months Fair Value	18,691,000				3,442,000
12 Months or More Fair Value	0				0
Total Fair Value	18,691,000				3,442,000
Individual securities in continuous unrealized loss position, aggregate losses [Abstract]
Less Than 12 Months Unrealized Loss	39,000				12,000
12 Months or More Unrealized Loss	0				0
Total Unrealized Loss	39,000				12,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	50,128,000		344,000		22,558,000
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	825,000		10,067,000		10,173,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Fair/Book Value, Total	825,000		10,067,000		10,173,000
Fair/Book Value [Abstract]
Fair/Book Value, Total	$ 825,000		$ 10,067,000		$ 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.