Derivatives (Offsetting Derivative Assets and Liabilities Subject to Master Netting Arrangements) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross Amounts Recognized, Derivative Assets	$ 32,718	$ 16,167
Gross Amounts Offset in the Statement of Income, Derivative Assets	(32,694)	(12,842)
Net Amounts Presented in the Statement of Income, Derivative Assets	24	3,325
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Assets	24	1,846
Net Amounts Presented in the Statement of Income, Derivative Assets		1,479
Gross Amounts Recognized, Derivative Liabilities	79,900	23,811
Gross Amounts Offset in the Statement of Income, Derivative Liabilities	(65,280)	(21,651)
Net Amounts Presented in the Statement of Income, Derivative Liabilities	14,620	2,160
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Liabilities	24	1,846
Gross Amounts Not offset in the Statement of Income - Cash Collateral, Derivative Liabilities	37,657	2,871
Net Amounts Presented in the Statement of Income, Derivative Liabilities	$ (23,061)	$ (2,557)