Investments (Debt maturities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale Securities, Amortized Cost:
One year or less	$ 0
After one year through five years	3,590
After five years through ten years	8,183
After ten years	49,210
Subtotal	60,983
Total securities	274,339
Available-for-sale Securities, Fair Value:
One year or less	0
After one year through five years	3,746
After five years through ten years	8,082
After ten years	51,821
Subtotal	63,649
Fair Value/ Carrying Value	280,169	219,039
Held-to-maturity Securities, Amortized Cost:
One year or less	503
After one year through five years	1,854
After five years through ten years	10,962
After ten years	1,507
Subtotal	14,826
Total securities	14,826	16,143
Held-to-maturity Securities, Fair Value:
One year or less	514
After one year through five years	1,985
After five years through ten years	12,069
After ten years	1,776
Subtotal	16,344
Fair Value	16,344
Mortgage-backed securities
Available-for-sale Securities, Amortized Cost:
No single maturity date	193,394
Available-for-sale Securities, Fair Value:
No single maturity	196,200
Held-to-maturity Securities, Amortized Cost:
No single maturity date	0
Held-to-maturity Securities, Fair Value:
No single maturity date	0
SBA Pools
Available-for-sale Securities, Amortized Cost:
No single maturity date	19,962
Available-for-sale Securities, Fair Value:
No single maturity	20,320
Fair Value/ Carrying Value	20,321
Held-to-maturity Securities, Amortized Cost:
No single maturity date	0
Held-to-maturity Securities, Fair Value:
No single maturity date	$ 0