Investments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Schedule of Available-for-sale Securities
Credit Loss Change, Available-for-Sale Investments	$ 0	$ 0

Amount of expense for allowance for credit loss on investment in debt security measured at fair value, with change in fair value recognized in other comprehensive income (available-for-sale) from transfer to investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8B
-URI http://asc.fasb.org/extlink&oid=121553693&loc=SL120268709-111562

Name:	us-gaap_DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration