Investment Securities (Details) (USD $)	3 Months Ended
	Mar. 31, 2013 Label Security	Dec. 31, 2012
Available-for-sale Securities [Abstract]
Amortized Cost	$ 376,554,000	$ 412,065,000
Gross Unrealized Gains	11,529,000	12,599,000
Gross Unrealized Losses	297,000	47,000
Fair Value	387,786,000	424,617,000
Held-to-maturity [Abstract]
Amortized Cost	167,617,000	153,524,000
Gross Unrealized Gains	3,160,000	3,407,000
Gross Unrealized Losses	600,000	7,000
Fair Value	170,177,000	156,924,000
Number of Private label Collateralized Mortgage Obligations	3
Combined balance of private-label collateralized mortgage obligations	83,000
Interest income on investment securities	73,000
Increase in diluted earnings per share on an annualized basis (in dollars per share)	$ 0.02
Available-for-sale, Amortized Cost [Abstract]
Due in one year or less	13,977,000
Due after one year through five years	44,507,000
Due after five years through ten years	22,706,000
Due after ten years	5,191,000
Other asset-backed securities	12,174,000
Mortgage-backed securities and collateralized mortgage obligations: Residential, Amortized Cost	249,083,000
Mortgage-backed securities and collateralized mortgage obligations: Commercial, Amortized Cost	28,452,000
Collateralized debt obligation	464,000
Available-for-sale securities, Amortized Cost	376,554,000
Available-for-sale, Fair Value [Abstract]
Due in one year or less	14,152,000
Due after one year through five years	46,369,000
Due after five years through ten years	24,462,000
Due after ten years	5,382,000
Other asset-backed securities	12,628,000
Mortgage-backed securities and collateralized mortgage obligations: Residential, Fair Value	254,573,000
Mortgage-backed securities and collateralized mortgage obligations: Commercial, Fair Value	29,693,000
Collateralized debt obligation, at fair Value	527,000
Available-for-sale securities, Fair Value	387,786,000
Held-to-maturity, Amortized Cost [Abstract]
Due in one year or less	306,000
Due after one year through five years	1,152,000
Due after five years through ten years	6,218,000
Due after ten years	36,767,000
Mortgage-backed securities and collateralized mortgage obligations: Residential, Amortized Cost	106,994,000
Mortgage-backed securities and collateralized mortgage obligations: Commercial, Amortized Cost	16,180,000
Held-to-maturity securities, Amortized Cost	167,617,000
Held-to-maturity, Fair Value [Abstract]
Due in one year or less	307,000
Due after one year through five years	1,154,000
Due after five years through ten years	6,329,000
Due after ten years	36,373,000
Mortgage-backed securities and collateralized mortgage obligations: Residential, Fair Value	109,190,000
Mortgage-backed securities and collateralized mortgage obligations: Commercial, Fair Value	16,824,000
Held-to-maturity securities, Fair Value	170,177,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Available-for-sale	60,233,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Available-for-sale	296,000
Securities with Losses over 12 Months, Fair Value, Available-for-sale	82,000
Securities with Losses over 12 Months, Gross Unrealized Loss, Available-for-sale	1,000
Total, Fair Value, Available-for-sale	60,315,000
Total, Gross Unrealized Loss, Available-for-sale	297,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Held-to-maturity	54,221,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Held-to-maturity	600,000
Securities with Losses over 12 Months, Fair Value, Held-to-maturity	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Held-to-maturity	0
Total securities, Fair Value, Held-to-maturity	54,221,000
Total securities, Gross Unrealized Loss, Held-to-maturity	600,000
Number of impairment related to credit quality	0
Number of impaired securities evaluated as other temporary	0
Impairment losses were recognized on debt securities	0
Number of available-for-sale securities sold	21
Available-for-sale securities, net gain	204,000
Number of available-for-sale securities sold with gains	18
Available-for-sale securities, gross realized gains	217,000
Number of available-for-sale securities sold with loss	3
Available-for-sale securities, gross realized losses	13,000
Securities pledged to secure public funds on deposits and for other purposes required or permitted by law	302,100,000	226,200,000
U.S. Government Sponsored Enterprises [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	13,195,000	13,422,000
Gross Unrealized Gains	8,000	2,000
Gross Unrealized Losses	17,000	0
Fair Value	13,186,000	13,424,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Available-for-sale	5,512,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Available-for-sale	17,000
Securities with Losses over 12 Months, Fair Value, Available-for-sale	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Available-for-sale	0
Total, Fair Value, Available-for-sale	5,512,000
Total, Gross Unrealized Loss, Available-for-sale	17,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Number of available-for-sale securities	4
Number of available-for-sale securities in unrealized loss positions	1
Obligation of State and Political Subdivisions [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	73,186,000	83,093,000
Gross Unrealized Gains	3,997,000	4,328,000
Gross Unrealized Losses	4,000	0
Fair Value	77,179,000	87,421,000
Held-to-maturity [Abstract]
Amortized Cost	44,443,000	42,900,000
Gross Unrealized Gains	201,000	7,000
Gross Unrealized Losses	481,000	7,000
Fair Value	44,163,000	42,900,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Available-for-sale	491,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Available-for-sale	4,000
Securities with Losses over 12 Months, Fair Value, Available-for-sale	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Available-for-sale	0
Total, Fair Value, Available-for-sale	491,000
Total, Gross Unrealized Loss, Available-for-sale	4,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Held-to-maturity	29,289,000	1,128,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Held-to-maturity	481,000	7,000
Securities with Losses over 12 Months, Fair Value, Held-to-maturity	0	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Held-to-maturity	0	0
Total securities, Fair Value, Held-to-maturity	29,289,000	1,128,000
Total securities, Gross Unrealized Loss, Held-to-maturity	481,000	7,000
Number of available-for-sale securities	122
Number of available-for-sale securities in unrealized loss positions	1
GSE Mortgage-Backed Securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	162,299,000	172,932,000
Gross Unrealized Gains	5,137,000	5,887,000
Gross Unrealized Losses	116,000	0
Fair Value	167,320,000	178,819,000
Held-to-maturity [Abstract]
Amortized Cost	91,968,000	89,383,000
Gross Unrealized Gains	2,315,000	2,819,000
Gross Unrealized Losses	29,000	0
Fair Value	94,254,000	92,202,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Available-for-sale	34,310,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Available-for-sale	116,000
Securities with Losses over 12 Months, Fair Value, Available-for-sale	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Available-for-sale	0
Total, Fair Value, Available-for-sale	34,310,000
Total, Gross Unrealized Loss, Available-for-sale	116,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Held-to-maturity	9,996,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Held-to-maturity	29,000
Securities with Losses over 12 Months, Fair Value, Held-to-maturity	0
Securities with Losses over 12 Months, Gross Unrealized Loss, Held-to-maturity	0
Total securities, Fair Value, Held-to-maturity	9,996,000
Total securities, Gross Unrealized Loss, Held-to-maturity	29,000
Number of available-for-sale securities	82
Number of available-for-sale securities in unrealized loss positions	8
Other Asset-Backed Securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	12,174,000	12,245,000
Gross Unrealized Gains	454,000	497,000
Gross Unrealized Losses	0	0
Fair Value	12,628,000	12,742,000
Collateralized Mortgage Obligations: Residential [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	86,784,000	101,381,000
Gross Unrealized Gains	629,000	652,000
Gross Unrealized Losses	160,000	47,000
Fair Value	87,253,000	101,986,000
Held-to-maturity [Abstract]
Amortized Cost	15,026,000	5,009,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	90,000	0
Fair Value	14,936,000	5,009,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Available-for-sale	19,920,000	10,085,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Available-for-sale	159,000	45,000
Securities with Losses over 12 Months, Fair Value, Available-for-sale	82,000	96,000
Securities with Losses over 12 Months, Gross Unrealized Loss, Available-for-sale	1,000	2,000
Total, Fair Value, Available-for-sale	20,002,000	10,181,000
Total, Gross Unrealized Loss, Available-for-sale	160,000	47,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Securities with Losses Under 12 Months, Fair Value, Held-to-maturity	14,936,000
Securities with Losses under 12 Months, Gross Unrealized Loss, Held-to-maturity	90,000
Total securities, Fair Value, Held-to-maturity	14,936,000
Total securities, Gross Unrealized Loss, Held-to-maturity	90,000
Number of available-for-sale securities	36
Number of available-for-sale securities in unrealized loss positions	7
Collateralized Mortgage Obligations: Commercial [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	28,452,000	28,528,000
Gross Unrealized Gains	1,241,000	1,233,000
Gross Unrealized Losses	0	0
Fair Value	29,693,000	29,761,000
Held-to-maturity [Abstract]
Amortized Cost	16,180,000	16,232,000
Gross Unrealized Gains	644,000	581,000
Gross Unrealized Losses	0	0
Fair Value	16,824,000	16,813,000
Collateralized Debt Obligations [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	464,000	464,000
Gross Unrealized Gains	63,000	0
Gross Unrealized Losses	0	0
Fair Value	$ 527,000	$ 464,000