Loans and Allowance for Loan and Lease Losses Loans and Allowance for Loan and Lease Losses (Schedule of Loan Concentrations by States) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 23,154,988	$ 21,977,008
1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 4,953,936	$ 4,664,920
Percent of loans by state	100.00%	100.00%
California [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 1,280,243	$ 1,177,221
Percent of loans by state	25.80%	25.20%
New York [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 1,057,926	$ 977,146
Percent of loans by state	21.40%	20.90%
Florida [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 597,359	$ 645,020
Percent of loans by state	12.10%	13.80%
Virginia [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 189,869	$ 184,756
Percent of loans by state	3.80%	4.00%
New Jersey [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 189,018	$ 158,863
Percent of loans by state	3.80%	3.50%
Others [Member] | 1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and lease receivable, net of premiums, discounts and deferred fees and costs	$ 1,639,521	$ 1,521,914
Percent of loans by state	33.10%	32.60%