Securities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 security		Dec. 31, 2011 security		Dec. 31, 2010
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position total	13		18
Aggregate unrealized losses on debt securities	$ 9,119,000		$ 12,165,000
Securities available for sale and held to maturity pledged as collateral, fair value	386,500,000		558,200,000
Credit-related impairment losses recognized in earnings	221,000		191,000		417,000
Amortized cost of trust preferred securities of individual name issuers that are below investment grade	11,800,000
Unrealized losses of trust preferred securities of individual name issuers that are below investment grade	2,600,000
Amortized cost of the first trust preferred security of pooled issuers on nonaccrual status	2,800,000
Total credit-related impairment losses of the first trust preferred security of pooled issuers on nonaccrual status	2,100,000
Current credit-related impairment losses of the first trust preferred security on nonaccrual status	212,000
Unrealized losses of the first trust preferred security of pooled issuers on nonaccrual status	2,200,000
Amortized cost of the second trust preferred security of pooled issuers on nonaccrual status	1,300,000
Total credit-related impairment losses of the second trust preferred security of pooled issuers on nonaccrual status	1,200,000
Unrealized losses of the second trust preferred security of pooled issuers on nonaccrual status	1,000,000
Amortized cost of callable debt securities	91,900,000
Callable debt securities, fair value	86,300,000
Minimum [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Callable debt securities, maturity period	45 months
Callable debt securities, call feature period	1 month
Maximum [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Callable debt securities, maturity period	25 years
Callable debt securities, call feature period	5 years
Trust Preferred Securities Individual Name Issuers [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position total	11		11
Securities in continuous unrealized loss position, number of companies issuing securities	7
Available for sale debt securities amortized cost	30,677,000	[1]	30,639,000	[1]
Aggregate unrealized losses on debt securities	5,926,000		8,243,000
Trust Preferred Securities Pooled Issuers [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position total	2		2
Available for sale debt securities amortized cost	4,036,000	[1]	4,256,000	[1]
Aggregate unrealized losses on debt securities	$ 3,193,000		$ 3,369,000

[1] Net of other-than-temporary impairment losses.