Loans (Summary of Recorded Investment of Consumer Loans by Risk Rating Categories) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	$ 1,971,001	$ 1,902,915	$ 1,833,108
Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	898,816	883,835	873,214
Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	577,241	546,036	535,283
Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	494,944	473,044	424,611
Originated Loans [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	1,920,343	1,847,184	1,772,063
Originated Loans [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	886,194	869,870	857,015
Originated Loans [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	574,906	544,078	532,883
Originated Loans [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	459,243	433,236	382,165
Originated Loans [Member] | Performing [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	1,903,387	1,827,955	1,749,361
Originated Loans [Member] | Performing [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	873,543	854,882	839,464
Originated Loans [Member] | Performing [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	574,354	543,339	531,701
Originated Loans [Member] | Performing [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	455,490	429,734	378,196
Originated Loans [Member] | Nonperforming [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	16,956	19,229	22,702
Originated Loans [Member] | Nonperforming [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	12,651	14,988	17,551
Originated Loans [Member] | Nonperforming [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	552	739	1,182
Originated Loans [Member] | Nonperforming [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	3,753	3,502	3,969
Acquired Loans [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	50,658	55,731	61,045
Acquired Loans [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	12,622	13,965	16,199
Acquired Loans [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	2,335	1,958	2,400
Acquired Loans [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	35,701	39,808	42,446
Acquired Loans [Member] | Performing [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	50,540	55,438	60,307
Acquired Loans [Member] | Performing [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	12,622	13,843	15,773
Acquired Loans [Member] | Performing [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	2,335	1,958	2,400
Acquired Loans [Member] | Performing [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	35,583	39,637	42,134
Acquired Loans [Member] | Nonperforming [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	118	293	738
Acquired Loans [Member] | Nonperforming [Member] | Real estate residential [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	0	122	426
Acquired Loans [Member] | Nonperforming [Member] | Consumer installment [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	0	0	0
Acquired Loans [Member] | Nonperforming [Member] | Home equity [Member]
Recorded investment of loans in consumer loan portfolio based on credit risk profile of loans in performing and nonperforming status
Recorded investment (loan balance), Consumer, Total	$ 118	$ 171	$ 312