Summary of Significant Accounting Policies (New Accounting Pronouncements Adopted) (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019		Dec. 31, 2018	Jan. 01, 2018	[2]
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Cumulative effect of change in accounting principle			$ 10,510	[1]		$ (160)
Operating lease right-of-use assets		$ 99,973
Operating lease liabilities		108,083
Reserve for credit losses including unfunded credit commitments		358,287			$ 311,322
Retained Earnings
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Cumulative effect of change in accounting principle			10,510	[1]		$ (545)
Accounting Standards Update 2016-02
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Operating lease right-of-use assets			109,100
Operating lease liabilities			117,700
Accounting Standards Update 2016-02 | Retained Earnings
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Cumulative effect of change in accounting principle			$ 10,500
Accounting Standards Update 2016-13
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Reserve for credit losses including unfunded credit commitments		$ 369,400
Accounting Standards Update 2016-13 | Subsequent Event
New Accounting Pronouncements Adopted and Recent Accounting Pronouncements [Line Items]
Percentage increase to reserve for credit losses, including unfunded credit commitments	34.00%

[1] Represents the impact of the adoption of ASU 2016-02, Leases (Topic 842) and subsequent related ASUs in the first quarter of 2019. Refer to Note 1 — Summary of Significant Accounting Policies and Note 10 — Leases to the Consolidated Financial Statements in this Form 10-K for additional information.

[2] Represents the impact of the adoption of Accounting Standards Update (“ASU”) 2016-01, Financial Instruments — Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities in the first quarter of 2018. Refer to Note 1 — Summary of Significant Accounting Policies to the Consolidated Financial Statements in this Annual Report on Form 10-K (“this Form 10-K”) for additional information.