Investment Securities (Available-for-sale Securities with Unrealized Loss) (Details) (USD $)	Mar. 31, 2015 securities	Dec. 31, 2014 securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 122,173,000	$ 116,660,000
Less than 12 months, unrealized loss	1,108,000	1,105,000
Less than 12 months, no. of securities	45	27
12 months or more, fair value	131,520,000	244,021,000
12 months or more, unrealized loss	4,183,000	7,675,000
12 months or more, no. of securities	41	73
Total unrealized loss position, fair value	253,693,000	360,681,000
Total unrealized loss	5,291,000	8,780,000
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	5,706,000	2,602,000
Less than 12 months, unrealized loss	54,000	12,000
Less than 12 months, no. of securities	10	4
12 months or more, fair value	214,000	5,788,000
12 months or more, unrealized loss	8,000	47,000
12 months or more, no. of securities	1	8
Total unrealized loss position, fair value	5,920,000	8,390,000
Total unrealized loss	62,000	59,000
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	108,910,000	114,018,000
Less than 12 months, unrealized loss	1,034,000	1,091,000
Less than 12 months, no. of securities	31	21
12 months or more, fair value	128,705,000	216,224,000
12 months or more, unrealized loss	3,603,000	6,773,000
12 months or more, no. of securities	36	57
Total unrealized loss position, fair value	237,615,000	330,242,000
Total unrealized loss	4,637,000	7,864,000
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	7,516,000	0
Less than 12 months, unrealized loss	19,000	0
Less than 12 months, no. of securities	2	0
12 months or more, fair value	0	19,404,000
12 months or more, unrealized loss	0	286,000
12 months or more, no. of securities	0	4
Total unrealized loss position, fair value	7,516,000	19,404,000
Total unrealized loss	19,000	286,000
Bank-issued trust preferred 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	2,505,000	2,509,000
12 months or more, unrealized loss	493,000	490,000
12 months or more, no. of securities	3	3
Total unrealized loss position, fair value	2,505,000	2,509,000
Total unrealized loss	493,000	490,000
Number of bank-issued trust preferred securities in unrealized loss position for twelve months or more	3
Equity securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	41,000	40,000
Less than 12 months, unrealized loss	1,000	2,000
Less than 12 months, no. of securities	2	2
12 months or more, fair value	96,000	96,000
12 months or more, unrealized loss	79,000	79,000
12 months or more, no. of securities	1	1
Total unrealized loss position, fair value	137,000	136,000
Total unrealized loss	80,000	81,000
Mortgage-backed securities, issued by US government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Percentage of mortgage-backed securities in unrealized loss position for more than 12 months	99.00%
Mortgage-backed securities, privately issued
Available-for-sale securities that had an unrealized loss:
Less than 12 months, no. of securities	3
Percentage of mortgage-backed securities in unrealized loss position for more than 12 months	1.00%
Number of privately issued mortgage-backed securities securities with book value less than 90% of fair value	2
Fair value within book value	90.00%
Fair Value Less Than 90 Percent of Book Value [Member] | Mortgage-backed securities, privately issued
Available-for-sale securities that had an unrealized loss:
12 months or more, fair value	600,000
Book value of privately issued mortgage-backed securities in unrealized loss position for more than 12 months	$ 900,000