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
Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	$ 24,998	$ 23,110
Provision charged to operating expenses	1,500us-gaap_ProvisionForLoanAndLeaseLosses	900us-gaap_ProvisionForLoanAndLeaseLosses
Recoveries of loans previously charged-off	76	1,444
Loans charged-off	(819)	(1,520)
Allowance for loan losses, ending	25,755	23,934
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	11,714	8,178
Provision charged to operating expenses	530	(915)
Recoveries of loans previously charged-off	54	1,005
Loans charged-off	(279)	(354)
Allowance for loan losses, ending	12,019	7,914
Commercial tax-exempt [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	55	72
Provision charged to operating expenses	(3)	(4)
Recoveries of loans previously charged-off	0	0
Loans charged-off	0	0
Allowance for loan losses, ending	52	68
Owner occupied real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	1,931	2,180
Provision charged to operating expenses	66	(162)
Recoveries of loans previously charged-off	0	243
Loans charged-off	(53)	(25)
Allowance for loan losses, ending	1,944	2,236
Commercial construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	4,242	5,559
Provision charged to operating expenses	285	195
Recoveries of loans previously charged-off	2	100
Loans charged-off	0	(12)
Allowance for loan losses, ending	4,529	5,842
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	4,707	4,161
Provision charged to operating expenses	688	1,122
Recoveries of loans previously charged-off	7	73
Loans charged-off	(457)	(716)
Allowance for loan losses, ending	4,945	4,640
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	796	960
Provision charged to operating expenses	20	346
Recoveries of loans previously charged-off	1	0
Loans charged-off	(14)	(283)
Allowance for loan losses, ending	803	1,023
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	931	1,303
Provision charged to operating expenses	(57)	133
Recoveries of loans previously charged-off	12	23
Loans charged-off	(16)	(130)
Allowance for loan losses, ending	870	1,329
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning	622	697
Provision charged to operating expenses	(29)	185
Recoveries of loans previously charged-off	0	0
Loans charged-off	0	0
Allowance for loan losses, ending	$ 593	$ 882

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(4)

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Paragraph 7

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1

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Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

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-Subparagraph (a)

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-Topic 942

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-Subparagraph (SX 210.9-04.11)

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