Investments in Affiliates Accounted for Using the Equity Method (Investment in Lending Tree) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Carrying amount	$ 167,121		$ 167,121		$ 167,643
Share of earnings (loss) of affiliates, net	$ 2,238	$ (1,068)	$ 1,531	$ (4,364)
LendingTree
Schedule of Equity Method Investments [Line Items]
Percentage ownership	26.40%		26.40%
Market value	$ 997,138		$ 997,138
Carrying amount	166,308		166,308		166,465
Share of earnings (loss) of affiliates, net	2,600	$ (1,300)	1,800	$ (3,400)
Other
Schedule of Equity Method Investments [Line Items]
Carrying amount	$ 813		$ 813		$ 1,178