New Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Other operating expenses	$ 72,452	$ 63,013
ASU 2018-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification adjustment related to cash flow hedges and investment portfolio credit risk	3,000
ASU 2016-18 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Decrease in net cash provided by operating activities		$ 73,000
ASU 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect on retained earnings	3,900
Capital raising and advisory fee revenues	8,600
Other operating expenses	$ 8,600