Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 5) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jul. 02, 2012
Recorded Investment
With no related allowance recorded	$ 94,085,000	$ 130,354,000	$ 94,085,000	$ 130,354,000	$ 119,511,000
With an allowance recorded	24,444,000	43,428,000	24,444,000	43,428,000	19,081,000
Total impaired loans	118,529,000	173,782,000	118,529,000	173,782,000	138,592,000
Unpaid Contractual Principal Balance
With no related allowance recorded	118,650,000	165,042,000	118,650,000	165,042,000	162,309,000
With an allowance recorded	26,821,000	56,157,000	26,821,000	56,157,000	20,293,000
Total impaired loans	145,471,000	221,199,000	145,471,000	221,199,000	182,602,000
Related Allowance
Total impaired loans	2,960,000	7,550,000	2,960,000	7,550,000	2,403,000
Average Recorded Investment
With no related allowance recorded	92,076,000	116,569,000	101,221,000	110,931,000
With an allowance recorded	29,106,000	45,792,000	25,764,000	46,887,000
Total impaired loans	121,182,000	162,361,000	126,985,000	157,818,000
Interest Income Recognized
With no related allowance recorded	1,449,000	220,000	2,499,000	405,000
With an allowance recorded	500,000		927,000
Total impaired loans	1,949,000	220,000	3,426,000	405,000
Minimum limit for nonperforming loans to be individually evaluated for impairment		500,000		500,000		1,000,000
Minimum limit for measuring impairment at the relationship level for borrowers with multiple loans exceeding $1,000,000						1,000,000
Outstanding loan amount of previously reported impaired loans under $1,000,000	6,300,000		6,300,000
Commercial
Recorded Investment
With no related allowance recorded	27,276,000	32,378,000	27,276,000	32,378,000	18,761,000
With an allowance recorded	7,639,000	10,766,000	7,639,000	10,766,000	7,516,000
Total impaired loans	34,915,000	43,144,000	34,915,000	43,144,000	26,277,000
Unpaid Contractual Principal Balance
With no related allowance recorded	28,029,000	43,247,000	28,029,000	43,247,000	24,135,000
With an allowance recorded	9,170,000	11,591,000	9,170,000	11,591,000	8,038,000
Total impaired loans	37,199,000	54,838,000	37,199,000	54,838,000	32,173,000
Related Allowance
Total impaired loans	478,000	2,850,000	478,000	2,850,000	952,000
Average Recorded Investment
With no related allowance recorded	23,171,000	30,100,000	21,701,000	23,451,000
With an allowance recorded	7,606,000	11,680,000	7,576,000	12,995,000
Total impaired loans	30,777,000	41,780,000	29,277,000	36,446,000
Interest Income Recognized
With no related allowance recorded	428,000		847,000
With an allowance recorded	311,000		357,000
Total impaired loans	739,000		1,204,000
Commercial real estate mortgages
Recorded Investment
With no related allowance recorded	26,821,000	28,368,000	26,821,000	28,368,000	42,882,000
With an allowance recorded	15,111,000	17,123,000	15,111,000	17,123,000	10,203,000
Total impaired loans	41,932,000	45,491,000	41,932,000	45,491,000	53,085,000
Unpaid Contractual Principal Balance
With no related allowance recorded	31,116,000	33,107,000	31,116,000	33,107,000	49,110,000
With an allowance recorded	15,963,000	18,266,000	15,963,000	18,266,000	10,783,000
Total impaired loans	47,079,000	51,373,000	47,079,000	51,373,000	59,893,000
Related Allowance
Total impaired loans	2,252,000	2,282,000	2,252,000	2,282,000	1,326,000
Average Recorded Investment
With no related allowance recorded	28,112,000	21,188,000	33,035,000	20,748,000
With an allowance recorded	14,228,000	12,711,000	12,886,000	12,077,000
Total impaired loans	42,340,000	33,899,000	45,921,000	32,825,000
Interest Income Recognized
With no related allowance recorded	427,000	55,000	662,000	124,000
With an allowance recorded	148,000		316,000
Total impaired loans	575,000	55,000	978,000	124,000
Residential mortgage
Recorded Investment
With no related allowance recorded	6,285,000	8,087,000	6,285,000	8,087,000	8,347,000
With an allowance recorded	1,694,000	5,547,000	1,694,000	5,547,000	463,000
Total impaired loans	7,979,000	13,634,000	7,979,000	13,634,000	8,810,000
Unpaid Contractual Principal Balance
With no related allowance recorded	6,975,000	9,206,000	6,975,000	9,206,000	9,194,000
With an allowance recorded	1,688,000	6,304,000	1,688,000	6,304,000	507,000
Total impaired loans	8,663,000	15,510,000	8,663,000	15,510,000	9,701,000
Related Allowance
Total impaired loans	230,000	398,000	230,000	398,000	9,000
Average Recorded Investment
With no related allowance recorded	7,124,000	8,660,000	7,532,000	8,167,000
With an allowance recorded	847,000	4,657,000	719,000	3,760,000
Total impaired loans	7,971,000	13,317,000	8,251,000	11,927,000
Interest Income Recognized
With no related allowance recorded	79,000	39,000	111,000	39,000
With an allowance recorded	41,000		41,000
Total impaired loans	120,000	39,000	152,000	39,000
Fixed
Recorded Investment
With no related allowance recorded	2,008,000	1,830,000	2,008,000	1,830,000	3,482,000
With an allowance recorded		2,291,000		2,291,000	463,000
Unpaid Contractual Principal Balance
With no related allowance recorded	2,356,000	2,518,000	2,356,000	2,518,000	3,757,000
With an allowance recorded		2,353,000		2,353,000	507,000
Related Allowance
Total impaired loans		236,000		236,000	9,000
Average Recorded Investment
With no related allowance recorded	2,963,000	2,248,000	3,136,000	2,663,000
With an allowance recorded		2,316,000	154,000	1,716,000
Interest Income Recognized
With no related allowance recorded	24,000		42,000
Variable
Recorded Investment
With no related allowance recorded	4,277,000	6,257,000	4,277,000	6,257,000	4,865,000
With an allowance recorded	1,694,000	3,256,000	1,694,000	3,256,000
Unpaid Contractual Principal Balance
With no related allowance recorded	4,619,000	6,688,000	4,619,000	6,688,000	5,437,000
With an allowance recorded	1,688,000	3,951,000	1,688,000	3,951,000
Related Allowance
Total impaired loans	230,000	162,000	230,000	162,000
Average Recorded Investment
With no related allowance recorded	4,161,000	6,412,000	4,396,000	5,504,000
With an allowance recorded	847,000	2,341,000	565,000	2,044,000
Interest Income Recognized
With no related allowance recorded	55,000	39,000	69,000	39,000
With an allowance recorded	41,000		41,000
Real estate construction
Recorded Investment
With no related allowance recorded	30,446,000	57,764,000	30,446,000	57,764,000	45,510,000
With an allowance recorded		8,765,000		8,765,000
Total impaired loans	30,446,000	66,529,000	30,446,000	66,529,000	45,510,000
Unpaid Contractual Principal Balance
With no related allowance recorded	48,220,000	74,310,000	48,220,000	74,310,000	74,283,000
With an allowance recorded		18,575,000		18,575,000
Total impaired loans	48,220,000	92,885,000	48,220,000	92,885,000	74,283,000
Related Allowance
Total impaired loans		1,866,000		1,866,000
Average Recorded Investment
With no related allowance recorded	30,971,000	51,450,000	35,817,000	53,109,000
With an allowance recorded	6,425,000	15,658,000	4,283,000	16,900,000
Total impaired loans	37,396,000	67,108,000	40,100,000	70,009,000
Interest Income Recognized
With no related allowance recorded	481,000	126,000	845,000	242,000
With an allowance recorded			213,000
Total impaired loans	481,000	126,000	1,058,000	242,000
Construction
Recorded Investment
With no related allowance recorded	16,265,000	38,828,000	16,265,000	38,828,000	19,762,000
Unpaid Contractual Principal Balance
With no related allowance recorded	21,064,000	52,209,000	21,064,000	52,209,000	33,267,000
Average Recorded Investment
With no related allowance recorded	17,799,000	29,937,000	18,453,000	29,103,000
Interest Income Recognized
With no related allowance recorded	228,000	126,000	558,000	242,000
Land
Recorded Investment
With no related allowance recorded	14,181,000	18,936,000	14,181,000	18,936,000	25,748,000
With an allowance recorded		8,765,000		8,765,000
Unpaid Contractual Principal Balance
With no related allowance recorded	27,156,000	22,101,000	27,156,000	22,101,000	41,016,000
With an allowance recorded		18,575,000		18,575,000
Related Allowance
Total impaired loans		1,866,000		1,866,000
Average Recorded Investment
With no related allowance recorded	13,172,000	21,513,000	17,364,000	24,006,000
With an allowance recorded	6,425,000	15,658,000	4,283,000	16,900,000
Interest Income Recognized
With no related allowance recorded	253,000		287,000
With an allowance recorded			213,000
Home equity loans and lines of credit
Recorded Investment
With no related allowance recorded	3,257,000	3,207,000	3,257,000	3,207,000	3,562,000
With an allowance recorded		1,227,000		1,227,000	899,000
Total impaired loans	3,257,000	4,434,000	3,257,000	4,434,000	4,461,000
Unpaid Contractual Principal Balance
With no related allowance recorded	4,310,000	4,245,000	4,310,000	4,245,000	4,660,000
With an allowance recorded		1,421,000		1,421,000	965,000
Total impaired loans	4,310,000	5,666,000	4,310,000	5,666,000	5,625,000
Related Allowance
Total impaired loans		154,000		154,000	116,000
Average Recorded Investment
With no related allowance recorded	2,698,000	4,621,000	2,986,000	4,861,000
With an allowance recorded		1,086,000	300,000	1,155,000
Total impaired loans	2,698,000	5,707,000	3,286,000	6,016,000
Interest Income Recognized
With no related allowance recorded	34,000		34,000
Total impaired loans	34,000		34,000
Installment loan
Recorded Investment
With no related allowance recorded		550,000		550,000	449,000
Total impaired loans		550,000		550,000	449,000
Unpaid Contractual Principal Balance
With no related allowance recorded		927,000		927,000	927,000
Total impaired loans		927,000		927,000	927,000
Average Recorded Investment
With no related allowance recorded		550,000	150,000	586,000
Total impaired loans		550,000	150,000	586,000
Consumer Installment loan
Recorded Investment
With no related allowance recorded		550,000		550,000	449,000
Unpaid Contractual Principal Balance
With no related allowance recorded		927,000		927,000	927,000
Average Recorded Investment
With no related allowance recorded		550,000	150,000	586,000
Lease financing
Average Recorded Investment
With no related allowance recorded				9,000
Total impaired loans				$ 9,000