Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Mutual funds	$ 1,107	$ 1,098
Level 1
Mutual funds	1,107	1,098
Level 2
Mutual funds	0	0
Level 3
Mutual funds	$ 0	$ 0

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant