Securities (Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	$ 89,805
Available for sale debt securities maturities 1-5 years amortized cost	192,401
Available for sale debt securities maturities 5-10 years amortized cost	17,326
Available for sale debt securities maturities after 10 years amortized cost	37,422
Available for sale debt securities maturities total amortized cost	336,954
Available for sale debt securities maturities within 1 year weighted average yield	4.48%
Available for sale debt securities maturities 1-5 years weighted average yield	4.11%
Available for sale debt securities maturities 5-10 years weighted average yield	2.82%
Available for sale debt securities maturities after 10 years weighted average yield	1.46%
Available for sale debt securities maturities total weighted average yield	3.85%
Available for sale debt securities maturities within 1 year fair value	91,941
Available for sale debt securities maturities 1-5 years fair value	202,095
Available for sale debt securities maturities 5-10 years fair value	18,384
Available for sale debt securities maturities after 10 years fair value	37,785
Available for sale debt securities fair value	350,205
Held to maturity debt securities maturities total amortized cost	36,897	40,381
Held to maturity debt securities maturities within 1 year fair value	12,128
Held to maturity debt securities maturities 1-5 years fair value	20,407
Held to maturity debt securities maturities 5-10 years fair value	4,671
Held to maturity debt securities maturities after 10 years fair value	598
Held to maturity securities fair value	37,804	41,420
Obligations of U.S. government-sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	0
Available for sale debt securities maturities 1-5 years amortized cost	29,465
Available for sale debt securities maturities 5-10 years amortized cost	0
Available for sale debt securities maturities after 10 years amortized cost	0
Available for sale debt securities maturities total amortized cost	29,465
Available for sale debt securities maturities within 1 year weighted average yield	0.00%
Available for sale debt securities maturities 1-5 years weighted average yield	5.39%
Available for sale debt securities maturities 5-10 years weighted average yield	0.00%
Available for sale debt securities maturities after 10 years weighted average yield	0.00%
Available for sale debt securities maturities total weighted average yield	5.39%
Available for sale debt securities fair value	31,320	31,670
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	73,925
Available for sale debt securities maturities 1-5 years amortized cost	97,398
Available for sale debt securities maturities 5-10 years amortized cost	17,126
Available for sale debt securities maturities after 10 years amortized cost	5,472
Available for sale debt securities maturities total amortized cost	193,921
Available for sale debt securities maturities within 1 year weighted average yield	4.31%
Available for sale debt securities maturities 1-5 years weighted average yield	3.91%
Available for sale debt securities maturities 5-10 years weighted average yield	2.83%
Available for sale debt securities maturities after 10 years weighted average yield	2.30%
Available for sale debt securities maturities total weighted average yield	3.92%
Available for sale debt securities fair value	206,794	231,233
Held to maturity debt securities maturities within 1 year amortized cost	11,837
Held to maturity debt securities maturities 1-5 years amortized cost	19,917
Held to maturity debt securities maturities 5-10 years amortized cost	4,559
Held to maturity debt securities maturities after 10 years amortized cost	584
Held to maturity debt securities maturities total amortized cost	36,897	40,381
Held to maturity debt securities maturities within 1 year weighted average yield	2.11%
Held to maturity debt securities maturities 1-5 years weighted average yield	1.93%
Held to maturity debt securities maturities 5-10 years weighted average yield	1.80%
Held to maturity debt securities maturities after 10 years weighted average yield	0.97%
Held to maturity debt securities maturities total weighted average yield	1.96%
Held to maturity securities fair value	37,804	41,420
States and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	7,665
Available for sale debt securities maturities 1-5 years amortized cost	59,837
Available for sale debt securities maturities 5-10 years amortized cost	0
Available for sale debt securities maturities after 10 years amortized cost	0
Available for sale debt securities maturities total amortized cost	67,502
Available for sale debt securities maturities within 1 year weighted average yield	3.92%
Available for sale debt securities maturities 1-5 years weighted average yield	3.90%
Available for sale debt securities maturities 5-10 years weighted average yield	0.00%
Available for sale debt securities maturities after 10 years weighted average yield	0.00%
Available for sale debt securities maturities total weighted average yield	3.91%
Available for sale debt securities fair value	71,583	72,620
Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	0
Available for sale debt securities maturities 1-5 years amortized cost	0
Available for sale debt securities maturities 5-10 years amortized cost	0
Available for sale debt securities maturities after 10 years amortized cost	31,950
Available for sale debt securities maturities total amortized cost	31,950
Available for sale debt securities maturities within 1 year weighted average yield	0.00%
Available for sale debt securities maturities 1-5 years weighted average yield	0.00%
Available for sale debt securities maturities 5-10 years weighted average yield	0.00%
Available for sale debt securities maturities after 10 years weighted average yield	1.32%
Available for sale debt securities maturities total weighted average yield	1.32%
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	8,215
Available for sale debt securities maturities 1-5 years amortized cost	5,701
Available for sale debt securities maturities 5-10 years amortized cost	200
Available for sale debt securities maturities after 10 years amortized cost	0
Available for sale debt securities maturities total amortized cost	14,116
Available for sale debt securities maturities within 1 year weighted average yield	6.52%
Available for sale debt securities maturities 1-5 years weighted average yield	2.85%
Available for sale debt securities maturities 5-10 years weighted average yield	1.65%
Available for sale debt securities maturities after 10 years weighted average yield	0.00%
Available for sale debt securities maturities total weighted average yield	4.97%
Available for sale debt securities fair value	$ 14,530	$ 14,381