Allowance for Loan Losses and Credit Quality of Loans, Credit Quality by Loan Class (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Commercial Credit Exposure [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	$ 327,050	$ 332,240
Commercial Credit Exposure [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,702,926	1,652,553
Commercial Credit Exposure [Member] | Pass [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	293,021	290,702
Commercial Credit Exposure [Member] | Pass [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,588,311	1,547,669
Commercial Credit Exposure [Member] | Special Mention [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	4,709	8,413
Commercial Credit Exposure [Member] | Special Mention [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	34,052	40,037
Commercial Credit Exposure [Member] | Substandard [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	29,320	33,125
Commercial Credit Exposure [Member] | Substandard [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	80,551	64,835
Commercial Credit Exposure [Member] | Doubtful [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Doubtful [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	12	12
Commercial Credit Exposure [Member] | Commercial [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	104,033	103,226
Commercial Credit Exposure [Member] | Commercial [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	635,094	616,423
Commercial Credit Exposure [Member] | Commercial [Member] | Pass [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	88,439	85,692
Commercial Credit Exposure [Member] | Commercial [Member] | Pass [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	585,553	576,079
Commercial Credit Exposure [Member] | Commercial [Member] | Special Mention [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	2,010	2,230
Commercial Credit Exposure [Member] | Commercial [Member] | Special Mention [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	12,755	16,836
Commercial Credit Exposure [Member] | Commercial [Member] | Substandard [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	13,584	15,304
Commercial Credit Exposure [Member] | Commercial [Member] | Substandard [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	36,786	23,508
Commercial Credit Exposure [Member] | Commercial [Member] | Doubtful [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Commercial [Member] | Doubtful [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	223,017	229,014
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	966,874	934,316
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Pass [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	204,582	205,010
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Pass [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	910,431	878,411
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Special Mention [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	2,699	6,183
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Special Mention [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	20,924	22,777
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Substandard [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	15,736	17,821
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Substandard [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	35,519	33,128
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Doubtful [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Doubtful [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	62,345	65,162
Commercial Credit Exposure [Member] | Agricultural [Member] | Pass [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | Pass [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	57,573	60,043
Commercial Credit Exposure [Member] | Agricultural [Member] | Special Mention [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | Special Mention [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	366	381
Commercial Credit Exposure [Member] | Agricultural [Member] | Substandard [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | Substandard [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	4,394	4,726
Commercial Credit Exposure [Member] | Agricultural [Member] | Doubtful [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Commercial Credit Exposure [Member] | Agricultural [Member] | Doubtful [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	12	12
Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	38,613	36,652
Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Pass [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	34,754	33,136
Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Special Mention [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	7	43
Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Substandard [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	3,852	3,473
Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Doubtful [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	0	0
Consumer Credit Exposure [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	199,196	219,587
Consumer Credit Exposure [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,789,834	1,752,950
Consumer Credit Exposure [Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,152	792
Consumer Credit Exposure [Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	10,620	10,222
Consumer Credit Exposure [Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	198,044	218,795
Consumer Credit Exposure [Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,779,214	1,742,728
Consumer Credit Exposure [Member] | Indirect [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	108,339	125,086
Consumer Credit Exposure [Member] | Indirect [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,217,426	1,161,844
Consumer Credit Exposure [Member] | Indirect [Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	179	164
Consumer Credit Exposure [Member] | Indirect [Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	2,835	3,044
Consumer Credit Exposure [Member] | Indirect [Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	108,160	124,922
Consumer Credit Exposure [Member] | Indirect [Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	1,214,591	1,158,800
Consumer Credit Exposure [Member] | Home Equity Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	84,345	87,076
Consumer Credit Exposure [Member] | Home Equity Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	517,464	532,823
Consumer Credit Exposure [Member] | Home Equity Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	920	570
Consumer Credit Exposure [Member] | Home Equity Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	7,657	7,046
Consumer Credit Exposure [Member] | Home Equity Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	83,425	86,506
Consumer Credit Exposure [Member] | Home Equity Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	509,807	525,777
Consumer Credit Exposure [Member] | Direct [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	6,512	7,425
Consumer Credit Exposure [Member] | Direct [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	54,944	58,283
Consumer Credit Exposure [Member] | Direct [Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	53	58
Consumer Credit Exposure [Member] | Direct [Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	128	132
Consumer Credit Exposure [Member] | Direct [Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	6,459	7,367
Consumer Credit Exposure [Member] | Direct [Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	54,816	58,151
Residential Mortgage Credit Exposure [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	300,360	308,416
Residential Mortgage Credit Exposure [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	756,433	733,221
Residential Mortgage Credit Exposure [Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	4,120	3,872
Residential Mortgage Credit Exposure [Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	7,349	7,913
Residential Mortgage Credit Exposure [Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	296,240	304,544
Residential Mortgage Credit Exposure [Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	749,084	725,308
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	300,360	308,416
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	756,433	733,221
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Nonperforming [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	4,120	3,872
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Nonperforming [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	7,349	7,913
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Performing [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	296,240	304,544
Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Performing [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	749,084	725,308
Business Banking Credit Exposure [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	68,492	70,149
Business Banking Credit Exposure [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	337,734	337,679
Business Banking Credit Exposure [Member] | Non-classified [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	63,332	65,437
Business Banking Credit Exposure [Member] | Non-classified [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	319,727	319,578
Business Banking Credit Exposure [Member] | Classified [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	5,160	4,712
Business Banking Credit Exposure [Member] | Classified [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	18,007	18,101
Business Banking Credit Exposure [Member] | Business Banking [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	68,492	70,149
Business Banking Credit Exposure [Member] | Business Banking [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	337,734	337,679
Business Banking Credit Exposure [Member] | Business Banking [Member] | Non-classified [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	63,332	65,437
Business Banking Credit Exposure [Member] | Business Banking [Member] | Non-classified [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	319,727	319,578
Business Banking Credit Exposure [Member] | Business Banking [Member] | Classified [Member] | ACQUIRED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	5,160	4,712
Business Banking Credit Exposure [Member] | Business Banking [Member] | Classified [Member] | ORIGINATED [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable	$ 18,007	$ 18,101