Components of Net Periodic Benefit Costs Summary of the Impact of Retrospective Application to the Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation and employee benefits	$ 21,362	$ 18,179	$ 61,285	$ 54,503
Other non-interest expense	$ 2,217	1,779	7,927	5,024
Defined contribution plan, employer contribution amount			$ 35,000
Previously Reported
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation and employee benefits		16,654		49,929
Other non-interest expense		$ 3,304		$ 9,599