Loans Receivable and Allowance for Loan Losses (Troubled Debt Restructurings on Loan Receivables) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Concessions	Jun. 30, 2012 QTD [Member] Contracts	Jun. 30, 2011 QTD [Member] Contracts	Jun. 30, 2012 YTD [Member] Contracts	Jun. 30, 2011 YTD [Member] Contracts	Jun. 30, 2012 Commercial and industrial [Member] QTD [Member] Contracts	Jun. 30, 2011 Commercial and industrial [Member] QTD [Member] Contracts	Jun. 30, 2012 Commercial and industrial [Member] YTD [Member] Contracts	Jun. 30, 2011 Commercial and industrial [Member] YTD [Member] Contracts	Jun. 30, 2012 Commercial tax-exempt [Member] QTD [Member] Contracts	Jun. 30, 2011 Commercial tax-exempt [Member] QTD [Member] Contracts	Jun. 30, 2012 Commercial tax-exempt [Member] YTD [Member] Contracts	Jun. 30, 2011 Commercial tax-exempt [Member] YTD [Member] Contracts	Jun. 30, 2012 Owner occupied real estate [Member] QTD [Member] Contracts	Jun. 30, 2011 Owner occupied real estate [Member] QTD [Member] Contracts	Jun. 30, 2012 Owner occupied real estate [Member] YTD [Member] Contracts	Jun. 30, 2011 Owner occupied real estate [Member] YTD [Member] Contracts	Jun. 30, 2012 Commercial construction and land development [Member] QTD [Member] Contracts	Jun. 30, 2011 Commercial construction and land development [Member] QTD [Member] Contracts	Jun. 30, 2012 Commercial construction and land development [Member] YTD [Member] Contracts	Jun. 30, 2011 Commercial construction and land development [Member] YTD [Member] Contracts	Jun. 30, 2012 Commercial real estate [Member] QTD [Member] Contracts	Jun. 30, 2011 Commercial real estate [Member] QTD [Member] Contracts	Jun. 30, 2012 Commercial real estate [Member] YTD [Member] Contracts	Jun. 30, 2011 Commercial real estate [Member] YTD [Member] Contracts	Jun. 30, 2012 Residential [Member] QTD [Member] Contracts	Jun. 30, 2011 Residential [Member] QTD [Member] Contracts	Jun. 30, 2012 Residential [Member] YTD [Member] Contracts	Jun. 30, 2011 Residential [Member] YTD [Member] Contracts	Jun. 30, 2012 Consumer [Member] QTD [Member] Contracts	Jun. 30, 2011 Consumer [Member] QTD [Member] Contracts	Jun. 30, 2012 Consumer [Member] YTD [Member] Contracts	Jun. 30, 2011 Consumer [Member] YTD [Member] Contracts
Financing Receivable, Modifications [Line Items]
Number of Contracts		4	2	11	4	1	1	1	3	0	0	0	0	0	0	0	0	1	0	5	0	0	0	1	0	1	1	2	1	1	0	2	0
Recorded Investment at Time of Restructure		$ 2,071	$ 3,710	$ 5,396	$ 12,236	$ 1,262	$ 3,516	$ 1,262	$ 12,042	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 351	$ 0	$ 3,396	$ 0	$ 0	$ 0	$ 68	$ 0	$ 280	$ 194	$ 475	$ 194	$ 178	$ 0	$ 195	$ 0
Number of concessions for classifying loans receivable as TDR	1