Loan and Lease Financings (Details 3) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	$ 4,653,085	$ 4,481,921
90 Days or More Past Due and Accruing	123	459
Total Accruing Loans	4,665,737	4,508,273
Nonaccrual	25,360	19,405
Total loans and leases	4,691,097	4,527,678
30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	11,549	20,360
60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	980	5,533
Commercial and agricultural
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	1,008,424	927,113
Total Accruing Loans	1,008,462	927,394
Nonaccrual	3,238	2,603
Total loans and leases	1,011,700	929,997
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	16	281
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	22	0
Auto and light truck
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	501,029	485,885
Total Accruing Loans	501,927	488,775
Nonaccrual	9,124	8,041
Total loans and leases	511,051	496,816
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	533	2,869
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	365	21
Medium and heavy duty truck
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	279,177	296,564
Total Accruing Loans	279,673	296,564
Nonaccrual	337	371
Total loans and leases	280,010	296,935
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	496	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
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	856,589	823,638
Total Accruing Loans	862,628	842,700
Nonaccrual	5,791	1,957
Total loans and leases	868,419	844,657
Aircraft | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	6,039	14,570
Aircraft | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	0	4,492
Construction equipment
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	615,738	561,665
Total Accruing Loans	618,221	562,446
Nonaccrual	998	991
Total loans and leases	619,219	563,437
Construction equipment | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	2,382	333
Construction equipment | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	101	448
Commercial real estate
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	744,355	738,006
Total Accruing Loans	745,035	738,150
Nonaccrual	3,891	3,418
Total loans and leases	748,926	741,568
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	680	23
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	121
Residential real estate and home equity
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	515,124	521,943
90 Days or More Past Due and Accruing	114	429
Total Accruing Loans	516,322	524,232
Nonaccrual	1,808	1,890
Total loans and leases	518,130	526,122
Residential real estate and home equity | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	657	1,508
Residential real estate and home equity | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	427	352
Consumer
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Current	132,649	127,107
90 Days or More Past Due and Accruing	9	30
Total Accruing Loans	133,469	128,012
Nonaccrual	173	134
Total loans and leases	133,642	128,146
Consumer | 30 to 59 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	746	776
Consumer | 60 to 89 Days Past Due
Recorded investment of loans and leases, segregated by class, with delinquency aging and nonaccrual status
Past Due	$ 65	$ 99