Loans Receivable - Aging Summary of Non-PCI Loans Held for Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Fair Value Less Unpaid Principal Balance, Past due	$ (1,246,865)
Current or less than 30 days past due
Financing Receivable, Past Due [Line Items]
Fair Value Less Unpaid Principal Balance, Not past due	(11,015)
30-59 days past due
Financing Receivable, Past Due [Line Items]
Fair Value Less Unpaid Principal Balance, Past due	0
60-89 days past due
Financing Receivable, Past Due [Line Items]
Fair Value Less Unpaid Principal Balance, Past due	0
90 days or more past due or nonaccrual
Financing Receivable, Past Due [Line Items]
Fair Value Less Unpaid Principal Balance, Past due	(1,235,850)
Non-PCI Loans
Financing Receivable, Past Due [Line Items]
Loan receivable past due		$ 1,352,476
Non-PCI Loans | Current or less than 30 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due		1,042,260
Non-PCI Loans | 30-59 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due		0
Non-PCI Loans | 60-89 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due		0
Non-PCI Loans | 90 days or more past due or nonaccrual
Financing Receivable, Past Due [Line Items]
Loan receivable past due		$ 310,216
Fair Value
Financing Receivable, Past Due [Line Items]
Loan receivable past due	1,325,144
Fair Value | Current or less than 30 days past due
Financing Receivable, Past Due [Line Items]
Current or less than 30 days past due	350,372
Fair Value | 30-59 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due	0
Fair Value | 60-89 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due	0
Fair Value | 90 days or more past due or nonaccrual
Financing Receivable, Past Due [Line Items]
Loan receivable past due	974,772
Carrying Value
Financing Receivable, Past Due [Line Items]
Loan receivable past due	2,572,009
Carrying Value | Current or less than 30 days past due
Financing Receivable, Past Due [Line Items]
Current or less than 30 days past due	361,387
Carrying Value | 30-59 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due	0
Carrying Value | 60-89 days past due
Financing Receivable, Past Due [Line Items]
Loan receivable past due	0
Carrying Value | 90 days or more past due or nonaccrual
Financing Receivable, Past Due [Line Items]
Loan receivable past due	$ 2,210,622