Revenue Recognition Contract Balances with Customers (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Receivables from Customers	$ 37,190	$ 37,190		$ 47,430
Contract with Customer, Asset, Net, Current	18	18		18
Contract with Customer, Asset, Net, Noncurrent	4,537	4,537		3,465
Customer deposits and refunds	971	971		$ 589
Increase (Decrease) in Receivables		(10,240)
Increase (Decrease) in Other Current Assets		0
Increase (Decrease) in Other Noncurrent Assets		1,072
Increase (Decrease) in Other Current Liabilities		382
Contract with Customer, Liability, Revenue Recognized	$ 200	$ 800	$ 700

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Amount of increase (decrease) in current assets classified as other.

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Amount of increase (decrease) in noncurrent assets classified as other.

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The increase (decrease) during the reporting period in the total amount due within one year (or one operating cycle) from all parties, associated with underlying transactions that are classified as operating activities.

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Amount due from customers for fees and charges arising from transactions related to the entity's brokerage activities and operations.

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