Fair Value Measurements and Fair Value of Financial Instruments (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 509,605	$ 414,507
Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	509,605	414,507
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	37,135	10,546
Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	470,419	401,846
Significant Unobservable Inputs (Level 3) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,051	2,115
U.S. treasury notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	20,632
U.S. treasury notes [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	20,632
U.S. treasury notes [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	20,632
Federal agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	28,438	24,969
Federal agency obligations [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	28,438	24,969
Federal agency obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		2,004
Federal agency obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	28,438	22,965
Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	59,499	115,364
Residential mortgage-backed securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	59,499	115,364
Residential mortgage-backed securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	59,499	115,364
Commercial mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	10,001
Commercial mortgage-backed securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	10,001	1,899
Commercial mortgage-backed securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	10,001
Commercial mortgage-backed securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		1,899
Obligations of U.S. states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	96,252	69,173
Obligations of U.S. states and political subdivisions [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	96,252	69,173
Obligations of U.S. states and political subdivisions [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		397
Obligations of U.S. states and political subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	96,252	68,776
Trust preferred securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,739	16,187
Trust preferred securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,739	16,187
Trust preferred securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,625	15,971
Trust preferred securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	114	216
Corporate bonds and notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236,715	173,117
Corporate bonds and notes [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236,715	173,117
Corporate bonds and notes [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		2,000
Corporate bonds and notes [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236,715	171,117
Collateralized mortgage obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,937	1,899
Collateralized mortgage obligations [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,937
Collateralized mortgage obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,937
Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	19,862	7,653
Asset-backed securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	19,862	7,653
Asset-backed securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	19,862	7,653
Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	3,027
Certificates of Deposit [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	3,027
Certificates of Deposit [Member] | Significant Other Observable Inputs (Level 2) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	3,027
Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	456	262
Equity securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	456	262
Equity securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	456	262
Other securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,047	5,883
Other securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,047	5,883
Other securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets Measured at Fair Value on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 16,047	$ 5,883