Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Other Commitments [Line Items]
Operating Lease, Right-of-Use Asset	$ 48,211
Operating Lease, Liability	$ 54,246
Operating Lease, Weighted Average Remaining Lease Term	7 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	3.20%
Operating Lease, Payments	$ 2,800
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	1,400
Operating Lease, Cost	2,820
Variable Lease, Cost	506
Sublease Income	(315)
Lease, Cost	3,011
Commitments to Extend Credit [Member]
Other Commitments [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	2,660,000	$ 2,620,000
Standby Letters of Credit [Member]
Other Commitments [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	27,600	28,300
Commercial Letter of Credit and other off-balance sheet liabilities [Member]
Other Commitments [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 0	$ 0