Operations and Summary of Significant Accounting Policies - Revision of Prior Period Financial Statements, Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Salaries and employee benefits	$ 100,791	$ 77,757	$ 177,984	$ 157,513
Other non-interest expense	12,606	10,734	22,866	23,175
Non-interest expense	222,352	141,718	387,769	283,234
Income before income taxes	(41,922)	99,199	(63,240)	203,311
Net income	(34,316)	77,812	(51,003)	159,513
Net income available to common stockholders	(36,753)	75,375	(55,878)	154,638
Comprehensive income	$ (38,609)	85,650	$ (59,477)	167,308
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Salaries and employee benefits		76,889		154,712
Other non-interest expense		11,445		24,681
Non-interest expense		141,561		281,939
Income before income taxes		99,356		204,606
Net income		77,969		160,808
Net income available to common stockholders		75,532		155,933
Comprehensive income		85,807		168,603
Revision of Prior Period, Error Correction, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Salaries and employee benefits		868		2,801
Other non-interest expense		(711)		(1,506)
Non-interest expense		157		1,295
Income before income taxes		(157)		(1,295)
Net income		(157)		(1,295)
Net income available to common stockholders		(157)		(1,295)
Comprehensive income		$ (157)		$ (1,295)