Commitments and Contingent Liabilities Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Loans Receivable [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	$ 10,000	$ 10,000	$ 10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	57,176	52,852	53,000
Loans Receivable [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Loans Receivable [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	57,176	52,852	53,000
Loans Receivable [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	25,865	26,787	45,721
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	193,926	191,903	170,842
Other Assets [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	13,861	14,783	17,816
Other Assets [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,964	10,964	11,430
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	150,778	153,506	141,231
Other Assets [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	1,040	1,040	16,475
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	43,148	38,397	29,611
Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	1,408
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	74,560	70,827	73,694
Other Liabilities [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other Liabilities [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	52,122	47,859	59,649
Other Liabilities [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	1,408
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	22,438	22,968	14,045
Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,964	10,964	11,811
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,964	10,964	10,964
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	847
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	22,313	22,967	29,150
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,958	11,927	14,119
Non-Controlling Interests [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	1,355	1,040	5,031
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	$ 0	$ 0	$ 0