Loan and Lease Financings (Details 3) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	$ 3,826,052	$ 3,632,003
90 Days or More Past Due and Accruing	278	982
Total Accruing Loans	3,837,617	3,653,972
Nonaccrual	15,082	34,602
Total loans and leases	3,852,699	3,688,574	$ 3,723,535
30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	2,657	3,363
60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	8,630	17,624
Commercial and agricultural
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	717,653	696,351
Total Accruing Loans	717,844	696,474
Nonaccrual	2,128	14,284
Total loans and leases	719,972	710,758	720,226
Commercial and agricultural | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	114	0
Commercial and agricultural | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	77	123
Auto and light truck
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	446,507	397,815
Total Accruing Loans	446,718	397,864
Nonaccrual	13	38
Total loans and leases	446,731	397,902	471,080
Auto and light truck | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	131	48
Auto and light truck | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	80	1
Medium and heavy duty truck
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	250,045	247,097
Total Accruing Loans	250,045	247,097
Nonaccrual	0	56
Total loans and leases	250,045	247,153	243,358
Medium and heavy duty truck | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	0	0
Medium and heavy duty truck | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	0	0
Aircraft financing
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	736,085	699,054
Total Accruing Loans	744,364	715,192
Nonaccrual	7,301	12,473
Total loans and leases	751,665	727,665	733,194
Aircraft financing | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	531	541
Aircraft financing | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	7,748	15,597
Construction equipment financing
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	444,001	396,821
Total Accruing Loans	444,747	399,189
Nonaccrual	732	751
Total loans and leases	445,479	399,940	369,755
Construction equipment financing | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	562	999
Construction equipment financing | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	184	1,369
Commercial real estate
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	638,832	611,780
Total Accruing Loans	638,832	611,780
Nonaccrual	2,373	4,807
Total loans and leases	641,205	616,587	602,321
Commercial real estate | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	0	0
Commercial real estate | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	0	0
Residential real estate
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	451,216	441,508
90 Days or More Past Due and Accruing	221	873
Total Accruing Loans	452,403	443,791
Nonaccrual	2,327	1,968
Total loans and leases	454,730	445,759	454,845
Residential real estate | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	640	1,099
Residential real estate | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	326	311
Consumer
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	141,713	141,577
90 Days or More Past Due and Accruing	57	109
Total Accruing Loans	142,664	142,585
Nonaccrual	208	225
Total loans and leases	142,872	142,810	$ 128,756
Consumer | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	679	676
Consumer | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	$ 215	$ 223