Summary of Significant Accounting Policies (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses		$ 138,150		$ 106,023	$ 106,693
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses			$ 110,027
Reserve for Unfunded Commitments			6,822
Total Reserve for Credit Losses			116,849
Accounting Standards Update 2016-13 | CECL Adoption Impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	$ (1,737)
Reserve for Unfunded Commitments	(3,335)
Total Reserve for Credit Losses	(5,072)
Retained Earnings
Total Pre-tax Impact	5,072
Tax Effect	(1,440)
Increase to Retained Earnings	3,632
Accounting Standards Update 2016-13 | January 1, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	108,290
Reserve for Unfunded Commitments	3,487
Total Reserve for Credit Losses	111,777
Commercial Loan | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses			73,801
Commercial Loan | Accounting Standards Update 2016-13 | CECL Adoption Impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	(18,789)
Commercial Loan | Accounting Standards Update 2016-13 | January 1, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	55,012
Consumer Loan | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses			$ 36,226
Consumer Loan | Accounting Standards Update 2016-13 | CECL Adoption Impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	17,052
Consumer Loan | Accounting Standards Update 2016-13 | January 1, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Allowance for Credit Losses	$ 53,278