Summary of Significant Accounting Policies - Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total	$ 298,742	$ 257,826
Retirement (annuity)
Segment Reporting Information [Line Items]
Total	209,231	174,661
Life
Segment Reporting Information [Line Items]
Total	59,478	53,974
Property and Casualty
Segment Reporting Information [Line Items]
Total	$ 30,033	$ 29,191

Net amount of deferred policy acquisition costs capitalized on contracts remaining in force as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 825
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6487548&loc=d3e32546-158582

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(7))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6481648&loc=d3e11198-158413

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 30
-Section 55
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68057816&loc=d3e11446-158418

Name:	us-gaap_DeferredPolicyAcquisitionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant