Allowance for Loan Losses Allowance by Impairment Analysis Method (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Acquired with Deteriorated Credit Quality	$ 0	$ 0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	74,393	80,680
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	1,978	3,377
Loans and Leases Receivable, Allowance	76,371	84,057	96,114	98,403
Financing Receivable, Collectively Evaluated for Impairment	5,048,392	4,732,612
Financing Receivable, Individually Evaluated for Impairment	64,067	81,524
Total loans	5,112,459	4,814,136
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	12,737	11,707
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	100	118
Loans and Leases Receivable, Allowance	12,837	11,825	12,163	13,438
Financing Receivable, Collectively Evaluated for Impairment	862,616	801,903
Financing Receivable, Individually Evaluated for Impairment	3,437	4,423
Total loans	866,053	806,326
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	44,249	50,830
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	730	1,667
Loans and Leases Receivable, Allowance	44,979	52,497	63,625	65,760
Financing Receivable, Collectively Evaluated for Impairment	1,772,785	1,632,698
Financing Receivable, Individually Evaluated for Impairment	40,609	58,652
Total loans	1,813,394	1,691,350
Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	4,229	4,827
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	236	189
Loans and Leases Receivable, Allowance	4,465	5,016	6,382	6,875
Financing Receivable, Collectively Evaluated for Impairment	150,087	135,357
Financing Receivable, Individually Evaluated for Impairment	3,830	2,213
Total loans	153,917	137,570
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	9,820	9,489
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	912	1,403
Loans and Leases Receivable, Allowance	10,732	10,892	9,286	7,449
Financing Receivable, Collectively Evaluated for Impairment	2,016,160	1,890,213
Financing Receivable, Individually Evaluated for Impairment	16,134	15,876
Total loans	2,032,294	1,906,089
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,020	1,085
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0
Loans and Leases Receivable, Allowance	1,020	1,085	1,535	1,231
Financing Receivable, Collectively Evaluated for Impairment	113,610	123,191
Financing Receivable, Individually Evaluated for Impairment	50	360
Total loans	113,660	123,551
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	322	540
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0
Loans and Leases Receivable, Allowance	322	540	1,149	1,478
Financing Receivable, Collectively Evaluated for Impairment	133,134	149,250
Financing Receivable, Individually Evaluated for Impairment	7	0
Total loans	133,141	149,250
Unallocated Financing Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,016	2,202
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0
Loans and Leases Receivable, Allowance	2,016	2,202	1,974	2,172
Financing Receivable, Collectively Evaluated for Impairment	0	0
Financing Receivable, Individually Evaluated for Impairment	0	0
Total loans	$ 0	$ 0