Cash Dividend (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
Aug. 10, 2017	Aug. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Cash Dividend [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.15
Payments of Ordinary Dividends, Common Stock		$ 6,600	$ 0	$ 6,632

Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration