Investments (Details 6) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investment securities continuous unrealized loss position
Fair Value of Investments with Unrealized Losses, Less Than 12 months	$ 50,561	$ 43,211
Gross Unrealized Loss, Less Than 12 Months	1,828	579
Fair Value of Investments with Unrealized Losses, 12 Months or Greater	2,345	10,610
Gross Unrealized Losses, 12 Months or Greater	181	1,231
Fair Value of Investments with Unrealized Losses, Total	52,906	53,821
Gross Unrealized Losses, Total	2,009	1,810
Total held-to-maturity securities [Member]
Investment securities continuous unrealized loss position
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Less Than 12 Months	22,764	25,899
Held-to-Maturity, Gross Unrealized Losses, Less Than 12 Months	118	148
Held-to-Maturity, Fair Value of Investments with Unrealized Losses 12 Months or Greater	2,345	10,610
Held-to-Maturity, Gross Unrealized Losses, 12 Months or Greater	181	1,231
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Total	25,109	36,509
Held-to-Maturity, Gross Unrealized Losses, Total	299	1,379
Total held-to-maturity securities [Member] | Corporate bonds [Member]
Investment securities continuous unrealized loss position
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Less Than 12 Months	10,734	23,063
Held-to-Maturity, Gross Unrealized Losses, Less Than 12 Months	12	130
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Total	10,734	23,063
Held-to-Maturity, Gross Unrealized Losses, Total	12	130
Total held-to-maturity securities [Member] | States and political subdivisions [Member]
Investment securities continuous unrealized loss position
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Less Than 12 Months	11,913	2,291
Held-to-Maturity, Gross Unrealized Losses, Less Than 12 Months	106	3
Held-to-Maturity, Fair Value of Investments with Unrealized Losses 12 Months or Greater		5,718
Held-to-Maturity, Gross Unrealized Losses, 12 Months or Greater		357
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Total	11,913	8,009
Held-to-Maturity, Gross Unrealized Losses, Total	106	360
Total held-to-maturity securities [Member] | U.S. agency-based mortgage-backed securities [Member]
Investment securities continuous unrealized loss position
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Less Than 12 Months	117
Held-to-Maturity, Fair Value of Investments with Unrealized Losses 12 Months or Greater	68	1,012
Held-to-Maturity, Gross Unrealized Losses, 12 Months or Greater	5	44
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Total	185	1,012
Held-to-Maturity, Gross Unrealized Losses, Total	5	44
Total held-to-maturity securities [Member] | Asset-backed securities [Member]
Investment securities continuous unrealized loss position
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Less Than 12 Months		545
Held-to-Maturity, Gross Unrealized Losses, Less Than 12 Months		15
Held-to-Maturity, Fair Value of Investments with Unrealized Losses 12 Months or Greater	2,277	3,880
Held-to-Maturity, Gross Unrealized Losses, 12 Months or Greater	176	830
Held-to-Maturity, Fair Value of Investments with Unrealized Losses, Total	2,277	4,425
Held-to-Maturity, Gross Unrealized Losses, Total	176	845
Total available-for-sale securities [Member]
Investment securities continuous unrealized loss position
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	27,797	17,312
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	1,710	431
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	27,797	17,312
Available-for Sale, Gross Unrealized Losses, Total	1,710	431
Fair Value of Investments with Unrealized Losses, 12 Months or Greater
Gross Unrealized Losses, 12 Months or Greater
Total available-for-sale securities [Member] | Corporate bonds [Member]
Investment securities continuous unrealized loss position
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	6,411	14,301
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	24	233
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	6,411	14,301
Available-for Sale, Gross Unrealized Losses, Total	24	233
Fair Value of Investments with Unrealized Losses, 12 Months or Greater
Gross Unrealized Losses, 12 Months or Greater
Total available-for-sale securities [Member] | States and political subdivisions [Member]
Investment securities continuous unrealized loss position
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	6,281	222
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	142	1
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	6,281	222
Available-for Sale, Gross Unrealized Losses, Total	142	1
Fair Value of Investments with Unrealized Losses, 12 Months or Greater
Gross Unrealized Losses, 12 Months or Greater
Total available-for-sale securities [Member] | U.S. agency-based mortgage-backed securities [Member]
Investment securities continuous unrealized loss position
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	10,919
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	859
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	10,919
Available-for Sale, Gross Unrealized Losses, Total	859
Fair Value of Investments with Unrealized Losses, 12 Months or Greater
Gross Unrealized Losses, 12 Months or Greater
Total available-for-sale securities [Member] | Equity Securities [Member]
Investment securities continuous unrealized loss position
Available-for Sale, Fair value of Investments with Unrealized Losses, Less Than 12 Months	4,186	2,789
Available-for Sale, Gross Unrealized Losses, Less Than 12 Months	685	197
Available-for Sale, Fair Value of Investments with Unrealized Losses, Total	4,186	2,789
Available-for Sale, Gross Unrealized Losses, Total	685	197
Fair Value of Investments with Unrealized Losses, 12 Months or Greater
Gross Unrealized Losses, 12 Months or Greater