Loans Receivable and Allowance for Loan Losses (Summary of Allowances on Loans Receivable, by Class) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	$ 23,934	$ 27,472	$ 23,110	$ 25,282
Provision charged to operating expenses	1,100	1,800	2,000	4,100
Recoveries of loans previously charged-off	535	228	1,979	894
Loans charged-off	(1,298)	(1,462)	(2,818)	(2,238)
Allowance for loan losses, ending	24,271	28,038	24,271	28,038
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	7,914	10,408	8,178	9,959
Provision charged to operating expenses	(557)	1,175	(1,472)	1,522
Recoveries of loans previously charged-off	244	194	1,249	332
Loans charged-off	(501)	(1,228)	(855)	(1,264)
Allowance for loan losses, ending	7,100	10,549	7,100	10,549
Commercial tax-exempt [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	68	75	72	83
Provision charged to operating expenses	(1)	(1)	(5)	(9)
Recoveries of loans previously charged-off	0	0	0	0
Loans charged-off	0	0	0	0
Allowance for loan losses, ending	67	74	67	74
Owner occupied real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	2,236	2,208	2,180	2,129
Provision charged to operating expenses	125	51	(37)	311
Recoveries of loans previously charged-off	43	0	286	3
Loans charged-off	(171)	(52)	(196)	(236)
Allowance for loan losses, ending	2,233	2,207	2,233	2,207
Commercial construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	5,842	7,967	5,559	7,222
Provision charged to operating expenses	1,270	(161)	1,465	115
Recoveries of loans previously charged-off	111	12	211	498
Loans charged-off	(527)	(8)	(539)	(25)
Allowance for loan losses, ending	6,696	7,810	6,696	7,810
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	4,640	5,038	4,161	3,983
Provision charged to operating expenses	99	162	1,221	1,299
Recoveries of loans previously charged-off	101	0	174	0
Loans charged-off	0	(141)	(716)	(223)
Allowance for loan losses, ending	4,840	5,059	4,840	5,059
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	1,023	338	960	324
Provision charged to operating expenses	37	539	383	666
Recoveries of loans previously charged-off	20	0	20	3
Loans charged-off	(19)	(14)	(302)	(130)
Allowance for loan losses, ending	1,061	863	1,061	863
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	1,329	787	1,303	793
Provision charged to operating expenses	68	468	201	767
Recoveries of loans previously charged-off	16	22	39	58
Loans charged-off	(80)	(19)	(210)	(360)
Allowance for loan losses, ending	1,333	1,258	1,333	1,258
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	882	651	697	789
Provision charged to operating expenses	59	(433)	244	(571)
Recoveries of loans previously charged-off	0	0	0	0
Loans charged-off	0	0	0	0
Allowance for loan losses, ending	$ 941	$ 218	$ 941	$ 218