Description of Business, Basis of Presentation and Significant Accounting Policies and Recently Issued Accounting Pronouncements - Recently Issued Accounting Pronouncements (Details) - USD ($) $ in Thousands			3 Months Ended	12 Months Ended
	Mar. 31, 2020	Jan. 01, 2020	Mar. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for Loan, Lease, and Other Losses			$ (7,946)	$ (920)
Financing Receivable, Allowance for Credit Loss	$ 47,540		$ 47,540
Accumulated Credit Losses, Increase (Decrease), Percentage to Loans Receivable	1.23%	1.01%	1.23%	(0.96%)
Financing Receivable, Purchase, Discount (Premium)		$ 10,000	$ 9,000	$ 8,400
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	$ 2,500
Effects of implementation of accounting change related to operating leases					$ (399)
Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		1,800
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase		1,600
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)		4,300
Effects of implementation of accounting change related to operating leases		(5,600)
Purchase Credit Impaired Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for Loan, Lease, and Other Losses		1,600
Unused Commitments to Extend Credit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for Loan, Lease, and Other Losses			(3,700)
Total Allowance for Credit Losses [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 47,540		$ 47,540
UNITED STATES
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Securities, Available-for-sale, Issuance Percent				83.50%
State and Local Jurisdiction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Securities, Available-for-sale, Issuance Percent				14.00%
Unused Commitments to Extend Credit and Total Accumulated Allowance Credit Losses [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effects of implementation of accounting change related to operating leases		7,100
Total Allowance for Credit Losses [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effects of implementation of accounting change related to operating leases		3,400
Unused Commitments to Extend Credit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effects of implementation of accounting change related to operating leases		$ 3,700			$ 0