Interest and Other Income (Loss), net - Schedule Of Interest And Other Income (Loss), net (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest And Other Income [Abstract]
Preferred equity investment income	$ 930	$ 961	$ 2,746	$ 3,327
Interest and other income	858	147	2,862	743
Mark-to-market of investments in our deferred compensation plans	990	812	1,280	3,536
Valuation allowance on preferred equity investment		(19,588)		(19,588)
Total interest and other income (loss), net	$ 2,778	$ (17,668)	$ 6,888	$ (11,982)

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.

Name:	us-gaap_InterestAndOtherIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration