Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	$ 53,446	$ 53,446	$ 61,503
Loans with a specific valuation allowance, Unpaid principal balance	56,319	56,319	63,406
Loans with a specific valuation allowance, Specific valuation allowance	9,442	9,442	11,949
Loans with a specific valuation allowance, Average balance	56,661	58,275	59,823
Loans without a specific valuation allowance, Recorded balance	130,627	130,627	138,177
Loans without a specific valuation allowance, Unpaid principal balance	160,293	160,293	169,082
Loans without a specific valuation allowance, Average balance	131,468	133,704	139,129
Recorded balance	184,073	184,073	199,680
Unpaid principal balance	216,612	216,612	232,488
Specific valuation allowance	9,442	9,442	11,949
Average balance	188,129	191,979	198,952
Residential Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	4,793	4,793	7,233
Loans with a specific valuation allowance, Unpaid principal balance	4,945	4,945	7,394
Loans with a specific valuation allowance, Specific valuation allowance	858	858	990
Loans with a specific valuation allowance, Average balance	5,438	6,036	7,237
Loans without a specific valuation allowance, Recorded balance	15,424	15,424	16,837
Loans without a specific valuation allowance, Unpaid principal balance	16,385	16,385	18,033
Loans without a specific valuation allowance, Average balance	15,381	15,866	18,103
Recorded balance	20,217	20,217	24,070
Unpaid principal balance	21,330	21,330	25,427
Specific valuation allowance	858	858	990
Average balance	20,819	21,902	25,340
Commercial Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	22,587	22,587	23,917
Loans with a specific valuation allowance, Unpaid principal balance	22,999	22,999	25,331
Loans with a specific valuation allowance, Specific valuation allowance	2,097	2,097	3,763
Loans with a specific valuation allowance, Average balance	24,817	24,517	26,105
Loans without a specific valuation allowance, Recorded balance	91,298	91,298	95,609
Loans without a specific valuation allowance, Unpaid principal balance	113,843	113,843	119,017
Loans without a specific valuation allowance, Average balance	91,487	92,861	95,808
Recorded balance	113,885	113,885	119,526
Unpaid principal balance	136,842	136,842	144,348
Specific valuation allowance	2,097	2,097	3,763
Average balance	116,304	117,378	121,913
Other Commercial
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	22,603	22,603	27,015
Loans with a specific valuation allowance, Unpaid principal balance	24,762	24,762	27,238
Loans with a specific valuation allowance, Specific valuation allowance	5,235	5,235	6,155
Loans with a specific valuation allowance, Average balance	22,699	24,137	22,460
Loans without a specific valuation allowance, Recorded balance	13,286	13,286	14,489
Loans without a specific valuation allowance, Unpaid principal balance	17,744	17,744	19,156
Loans without a specific valuation allowance, Average balance	13,761	14,003	14,106
Recorded balance	35,889	35,889	41,504
Unpaid principal balance	42,506	42,506	46,394
Specific valuation allowance	5,235	5,235	6,155
Average balance	36,460	38,140	36,566
Home Equity
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	1,011	1,011	886
Loans with a specific valuation allowance, Unpaid principal balance	1,109	1,109	949
Loans with a specific valuation allowance, Specific valuation allowance	244	244	265
Loans with a specific valuation allowance, Average balance	1,057	1,000	767
Loans without a specific valuation allowance, Recorded balance	7,677	7,677	8,153
Loans without a specific valuation allowance, Unpaid principal balance	9,178	9,178	9,631
Loans without a specific valuation allowance, Average balance	7,747	7,883	8,844
Recorded balance	8,688	8,688	9,039
Unpaid principal balance	10,287	10,287	10,580
Specific valuation allowance	244	244	265
Average balance	8,804	8,883	9,611
Other Consumer
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	2,452	2,452	2,452
Loans with a specific valuation allowance, Unpaid principal balance	2,504	2,504	2,494
Loans with a specific valuation allowance, Specific valuation allowance	1,008	1,008	776
Loans with a specific valuation allowance, Average balance	2,650	2,585	3,254
Loans without a specific valuation allowance, Recorded balance	2,942	2,942	3,089
Loans without a specific valuation allowance, Unpaid principal balance	3,143	3,143	3,245
Loans without a specific valuation allowance, Average balance	3,092	3,091	2,268
Recorded balance	5,394	5,394	5,541
Unpaid principal balance	5,647	5,647	5,739
Specific valuation allowance	1,008	1,008	776
Average balance	$ 5,742	$ 5,676	$ 5,522