Investment Securities (Available-for-sale Securities with Unrealized Loss) (Details) (USD $)	Mar. 31, 2013 securities	Dec. 31, 2012 securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 187,452,000	$ 149,865,000
Less than 12 months, unrealized loss	3,262,000	2,469,000
Less than 12 months, no. of securities	52	40
12 months or more, fair value	42,865,000	95,483,000
12 months or more, unrealized loss	4,488,000	8,190,000
12 months or more, no. of securities	18	26
Total fair value	230,317,000	245,348,000
Total unrealized loss	7,750,000	10,659,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities that had an unrealized loss:
Percentage of mortgage-backed securities in unrealized loss position for less than 12 months	92.00%
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale securities that had an unrealized loss:
Less than 12 months, no. of securities	6
Percentage of mortgage-backed securities in unrealized loss position for less than 12 months	8.00%
Fair value within book value	90.00%
U.S. Treasury and government agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	0	0
Less than 12 months, unrealized loss	0	0
Less than 12 months, no. of securities	0	0
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	0	0
Total unrealized loss	0	0
U.S. government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	0	0
Less than 12 months, unrealized loss	0	0
Less than 12 months, no. of securities	0	0
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	0	0
Total unrealized loss	0	0
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	9,120,000	4,558,000
Less than 12 months, unrealized loss	181,000	82,000
Less than 12 months, no. of securities	15	8
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	9,120,000	4,558,000
Total unrealized loss	181,000	82,000
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	168,316,000	135,250,000
Less than 12 months, unrealized loss	2,996,000	2,326,000
Less than 12 months, no. of securities	34	28
12 months or more, fair value	38,288,000	89,958,000
12 months or more, unrealized loss	3,802,000	7,441,000
12 months or more, no. of securities	13	20
Total fair value	206,604,000	225,208,000
Total unrealized loss	6,798,000	9,767,000
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	7,640,000	7,681,000
Less than 12 months, unrealized loss	67,000	43,000
Less than 12 months, no. of securities	2	2
12 months or more, fair value	0	0
12 months or more, unrealized loss	0	0
12 months or more, no. of securities	0	0
Total fair value	7,640,000	7,681,000
Total unrealized loss	67,000	43,000
Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	2,376,000	2,376,000
Less than 12 months, unrealized loss	18,000	18,000
Less than 12 months, no. of securities	1	2
12 months or more, fair value	4,487,000	5,434,000
12 months or more, unrealized loss	600,000	664,000
12 months or more, no. of securities	4	5
Total fair value	6,863,000	7,810,000
Total unrealized loss	618,000	682,000
Fair value within book value	90.00%
Number of available-for-sale securities in unrealized loss position	4
Equity Securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	0	0
Less than 12 months, unrealized loss	0	0
Less than 12 months, no. of securities	0	0
12 months or more, fair value	90,000	91,000
12 months or more, unrealized loss	86,000	85,000
12 months or more, no. of securities	1	1
Total fair value	90,000	91,000
Total unrealized loss	86,000	85,000
Fair Value Less Than 90 Percent of Book Value [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	1,500,000
Mortgage-backed securities in unrealized loss position for less than 12 months, aggregate book value	2,000,000
Fair Value Less Than 95 Percent of Book Value [Member] | Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Total fair value	2,400,000
Number of available-for-sale securities in unrealized loss position	1
Available-for-sale securities in unrealized loss position, aggregate book value	$ 3,000,000
Fair Value Within 95 Percent of Book Value [Member] | Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Number of available-for-sale securities in unrealized loss position	3