Investment in Unconsolidated Affiliate (Balance Sheets) (Details) - LSV Asset Management - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Current assets	$ 138,320	$ 138,083
Non-current assets	4,721	1,165
Total assets	143,041	139,248
Current liabilities	75,192	47,874
Non-current liabilities	4,738	0
Partners’ capital	63,111	91,374
Total liabilities and partners’ capital	$ 143,041	$ 139,248