Loans Receivable and Allowance for Credit Losses (Loan Purchases, Sales and Transfers) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	$ 49,040	$ 77,960	$ 222,434	$ 363,591
Loans transferred from held-for-sale to held-for-investment		2,306	0	2,306
Sales	55,663	93,418	229,182	386,621
Purchases	68,965	61,086	395,250	450,908
Write-down of loans transferred from loans held-for-investment to loans held-for-sale recorded to allowance for loan losses	36	110	426	13,500
Net gains from sales of loans held-for-sale during the period	2,000	1,100	3,000	5,100
Commercial and industrial (“C&I”) \| Originated
Loans Receivable and Allowance for Credit Losses
Sales	47,800		180,000	252,100
Commercial and industrial (“C&I”) \| Single-family residential \| Originated
Loans Receivable and Allowance for Credit Losses
Sales		58,900
Loans sold in secondary market \| Purchased
Loans Receivable and Allowance for Credit Losses
Sales	7,900	34,500	49,200	134,500
Commercial lending \| Commercial and industrial (“C&I”)
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	34,071	53,149	189,237	298,989
Loans transferred from held-for-sale to held-for-investment		2,306		2,306
Sales	37,986	62,744	189,663	305,435
Purchases	38,047	47,809	304,341	398,171
Commercial lending \| Commercial real estate (“CRE”)
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	14,969	9,830	31,624	49,621
Loans transferred from held-for-sale to held-for-investment		0		0
Sales	14,969	9,830	31,624	49,621
Purchases	0	0	0	0
Commercial lending \| Real estate loan \| Multifamily residential
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	0	0	0	0
Loans transferred from held-for-sale to held-for-investment		0		0
Sales	0	0	0	0
Purchases	1,350	2,518	7,302	5,953
Commercial lending \| Construction and land
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	0	0	1,573	0
Loans transferred from held-for-sale to held-for-investment		0		0
Sales	0	0	1,573	0
Purchases	0	0	0	0
Consumer lending \| Real estate loan \| Single-family residential
Loans Receivable and Allowance for Credit Losses
Loans transferred from held-for-investment to held-for-sale	0	14,981	0	14,981
Loans transferred from held-for-sale to held-for-investment		0		0
Sales	2,708	20,844	6,322	31,565
Purchases	$ 29,568	$ 10,759	$ 83,607	$ 46,784

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of increase from purchase of financing receivable.

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Amount of decrease from sale and reclassification to held-for-sale of financing receivable.

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The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans and leases that were sold during the reporting period. This element refers to the gain (loss) and not to the cash proceeds of the sales. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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Value of loans held-for-sale transferred to loans held in the entity's portfolio in noncash transactions.

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