Bank Deposits (Scheduled Maturities of Certificates of Deposit) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deposits Liabilities Balance Sheet Reported Amounts [Abstract]
Within one year	$ 5,305	$ 4,858
One to three years	360	623
Three to five years	13	140
Certificates of deposit, less than $100,000	5,678	5,621
Within one year	441,341	1,535,784
One to three years	68,855	195,159
Three to five years	7,084	26,772
Certificates of deposit, $100,000 and greater	517,280	1,757,715
Total certificates of deposit	$ 522,958	$ 1,763,336