Loans Receivable and Allowance for Loan Losses (Age Analysis of Past Due Loan Receivables) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Current	$ 1,877,943		$ 1,701,797
30-59 Days Past Due	12,117		16,234
60-89 Days Past Due	3,572		11,140
90 Days Past Due and Greater	19,988		21,701
Total Past Due	35,677		49,075
Total loans receivable	1,913,620		1,750,872
Recorded Investment in Loans 90 Days and Greater and Still Accruing	8		369
Transfer of loans to foreclosed assets	4,264	2,732
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	468,201		438,522
30-59 Days Past Due	6,450		1,830
60-89 Days Past Due	0		1,041
90 Days Past Due and Greater	3,954		5,751
Total Past Due	10,404		8,622
Total loans receivable	478,605		447,144
Recorded Investment in Loans 90 Days and Greater and Still Accruing	0		17
Commercial tax-exempt [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	75,986		81,734
30-59 Days Past Due	0		0
60-89 Days Past Due	0		0
90 Days Past Due and Greater	0		0
Total Past Due	0		0
Total loans receivable	75,986		81,734
Recorded Investment in Loans 90 Days and Greater and Still Accruing	0		0
Owner occupied real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	303,016		295,278
30-59 Days Past Due	2,175		2,618
60-89 Days Past Due	1,201		1,674
90 Days Past Due and Greater	5,640		2,847
Total Past Due	9,016		7,139
Total loans receivable	312,032		302,417
Recorded Investment in Loans 90 Days and Greater and Still Accruing	0		0
Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	122,262		124,240
30-59 Days Past Due	52		3,355
60-89 Days Past Due	0		342
90 Days Past Due and Greater	0		5,239
Total Past Due	52		8,936
Total loans receivable	122,314		133,176
Recorded Investment in Loans 90 Days and Greater and Still Accruing	0		0
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	587,144		465,765
30-59 Days Past Due	1,951		2,142
60-89 Days Past Due	969		444
90 Days Past Due and Greater	3,940		4,837
Total Past Due	6,860		7,423
Total loans receivable	594,004		473,188
Recorded Investment in Loans 90 Days and Greater and Still Accruing	8		235
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	101,929		85,352
30-59 Days Past Due	90		4,194
60-89 Days Past Due	1,171		6,304
90 Days Past Due and Greater	4,517		1,916
Total Past Due	5,778		12,414
Total loans receivable	107,707		97,766
Recorded Investment in Loans 90 Days and Greater and Still Accruing	0		117
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	219,405		210,906
30-59 Days Past Due	1,399		2,095
60-89 Days Past Due	231		1,335
90 Days Past Due and Greater	1,937		1,111
Total Past Due	3,567		4,541
Total loans receivable	222,972		215,447
Recorded Investment in Loans 90 Days and Greater and Still Accruing	$ 0		$ 0