Basis of Presentation (Other Expense (Income), Net) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounting Policies [Abstract]
Write-offs of deposits and pre-acquisition costs	$ (2,516)	$ (1,652)	$ (5,433)	$ (4,261)
Amortization of intangible assets	(3,550)	(3,450)	(7,000)	(6,900)
Loss on debt retirement (see Note 4)	(4,843)	(76)	(4,843)	(76)
Interest income	4,471	835	9,420	1,399
Interest expense	(146)	(165)	(290)	(308)
Equity in earnings of unconsolidated entities	129	265	165	1,226
Miscellaneous, net	2,956	2,287	3,508	5,657
Total other expense, net	$ (3,499)	$ (1,956)	$ (4,473)	$ (3,263)