Goodwill and Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
	Dec. 06, 2019	Nov. 01, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Goodwill and Intangible Assets [Line Items]
Amortization of intangible assets			$ 4,700	$ 3,500	$ 9,760	$ 7,140
Customer Relationships [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					10 years 2 months 12 days
Trade Name [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					9 years 4 months 24 days
Core Deposits [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					3 years 7 months 6 days
Non-Compete Agreements [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					6 years 4 months 24 days
Investment Banking Backlog [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					8 years 2 months 12 days
Acquired Technology [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted-average remaining lives of intangible assets					2 years 1 month 6 days
MainFirst Bank AG [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Date of acquisition		Jul. 01, 2019
GMP Capital Inc. [Member]
Schedule of Goodwill and Intangible Assets [Line Items]
Date of acquisition	Sep. 03, 2019