Fair Value Measurements - Fair Value of Other Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrowings under revolving credit facility	$ 0	$ 49,731
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Borrowings under revolving credit facility	$ 0	$ 49,731

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration