Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	$ 60,160	$ 48,294
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	46,545	59,697
Deferred Tax Liabilities, Intangible Assets	2,969	0
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	6,716	9,036
Deferred Tax Assets, Acquired Lease Liability	24,623	2,098
Deferred Tax Assets, Other	3,043	2,444
Deferred Tax Assets, Gross	144,056	121,569
Deferred Tax Assets, Valuation Allowance	(5,234)	(9,135)
Deferred Tax Assets, Net of Valuation Allowance	138,822	112,434
Deferred Tax Liabilities, Investments	23,028	0
Deferred Tax Liabilities, Unrealized Gains on Trading Securities	26,545	13,092
Deferred Tax Liabilities, Other	6,103	1,642
Deferred Tax Liabilities, Gross	(59,656)	(19,377)
Deferred Income Tax Expense (Benefit)	13,296	18,965	$ 41,170
Preferred stock dividends	6,792	6,792	$ 6,792
Deferred tax assets/(liabilities), net	79,166	93,057
Deferred Tax Liabilities, Deferred Expense	$ 3,980	$ 4,643