Derivative Instruments And Hedging Activities (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Other Comprehensvie Income Loss Reclassification Adjustment From AOCI on Derivative Instruments, Gross		$ 11,300	$ 9,000
Derivatives designated for hedges of investments in foreign operations		0
Derivative Liability, Fair Value, Gross Liability		59,200
Fair values of derivative assets reduced (increased) by net credit valuation adjustments		1,700	2,400
Cash collateral used to offset fair value amount under master neeting arrangements		0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 2,000
Notional amount of bank and insurance trust preferred CDOs		6,209,146	$ 5,147,068
Cash collateral pledged for derivative liabilities		43,800
Additional collateral that would be required to be pledge if credit rating was downgraded by one notch		1,100
Derivative Credit Risk Valuation Adjustment, Derivative Liabilities		$ 1,400