Investments - Additional Information (Details)	3 Months Ended
Mar. 31, 2019 USD ($) Issue	Mar. 31, 2018 USD ($)	Dec. 31, 2018 Issue
Gain (Loss) on Securities [Line Items]
Total issues of fixed maturity portfolio \| Issue	1,598		1,548
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Other than-temporary impairment, available for sale securities \| $	$ 0	$ 0

Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings and other comprehensive loss (OCI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=109979856&loc=SL6284422-111562

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