Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Allowance for loan losses:
Ending balance (total allowance)	$ 21,021	$ 29,227	$ 39,958	$ 43,693	$ 49,911	$ 28,419
Ending balance: individually evaluated for impairment	793		10,626
Ending balance: collectively evaluated for impairment	20,228		29,332
Loan balances:
Ending balance (loan portfolio) (1)	766,569		969,111
Ending balance: individually evaluated for impairment	29,721		135,100
Ending balance: collectively evaluated for impairment	736,848		834,011
Commercial and industrial loans [Member]
Allowance for loan losses:
Ending balance (total allowance)	9,936		25,080
Ending balance: individually evaluated for impairment	242		7,477
Ending balance: collectively evaluated for impairment	9,694		17,603
Loan balances:
Ending balance (loan portfolio) (1)	177,077		206,652
Ending balance: individually evaluated for impairment	11,597		36,559
Ending balance: collectively evaluated for impairment	165,480		170,093
Commercial real estate mortgages [Member]
Allowance for loan losses:
Ending balance (total allowance)	7,911		11,029
Ending balance: individually evaluated for impairment			3,092
Ending balance: collectively evaluated for impairment	7,911		7,937
Loan balances:
Ending balance (loan portfolio) (1)	340,581		428,646
Ending balance: individually evaluated for impairment	9,718		66,402
Ending balance: collectively evaluated for impairment	330,863		362,244
Real estate construction loans [Member]
Allowance for loan losses:
Ending balance (total allowance)	70		623
Ending balance: individually evaluated for impairment			57
Ending balance: collectively evaluated for impairment	70		566
Loan balances:
Ending balance (loan portfolio) (1)	23,781		49,704
Ending balance: individually evaluated for impairment	5,584		19,251
Ending balance: collectively evaluated for impairment	18,197		30,453
Residential mortgages (1st and 2nd liens) [Member]
Allowance for loan losses:
Ending balance (total allowance)	1,345		2,401
Ending balance: individually evaluated for impairment	550
Ending balance: collectively evaluated for impairment	795		2,401
Loan balances:
Ending balance (loan portfolio) (1)	138,934		160,619
Ending balance: individually evaluated for impairment	2,687		8,345
Ending balance: collectively evaluated for impairment	136,247		152,274
Home equity loans [Member]
Allowance for loan losses:
Ending balance (total allowance)	1,561		512
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	1,561		512
Loan balances:
Ending balance (loan portfolio) (1)	70,276		79,684
Ending balance: individually evaluated for impairment			3,897
Ending balance: collectively evaluated for impairment	70,276		75,787
Consumer and other loans [Member]
Allowance for loan losses:
Ending balance (total allowance)	198		313
Ending balance: individually evaluated for impairment	1
Ending balance: collectively evaluated for impairment	197		313
Loan balances:
Ending balance (loan portfolio) (1)	15,920		43,806
Ending balance: individually evaluated for impairment	135		646
Ending balance: collectively evaluated for impairment	$ 15,785		$ 43,160