Summary of Significant Accounting Policies - Summary of Appropriated Retained Earnings Amount Included in Retained Earnings (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Appropriated Retained Earnings [Abstract]
Appropriated retained earnings	$ 47,473	$ 43,151

A segregation of retained earnings which is unavailable for dividend distribution. Includes also retained earnings appropriated for loss contingencies.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant