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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 02, 2018	Jan. 01, 2018
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Depreciation expense	$ 9,000	$ 10,100	$ 11,200
Guarantee maturity value as percentage of net premiums	75.00%
Unearned premiums		14,900
Pre-tax gains and losses in realized investment gains (losses)	$ (2,456)
Equity securities, carrying value	34,997	0
Accounting Standards Update 2014-09 [Member]
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Cumulative effect of accounting standard adoption on retained earnings				$ 24,700
Percentage of cumulative effect of accounting standard adoption on retained earnings				1.70%
Additional revenue recognized	1,600
Accounting Standards Update 2016-01
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Cumulative effect of accounting standard adoption on increase retained earnings					$ 7,700
Decrease accumulated other comprehensive income (loss)					$ 7,700
Pre-tax gains and losses in realized investment gains (losses)	$ 2,500
Equity securities, carrying value		$ 1,400
Minimum [Member]
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Interest rate reserve assumptions	3.50%	3.50%
Maximum [Member]
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Interest rate reserve assumptions	7.00%	7.00%
Maximum [Member] \| Accounting Standards Update 2016-02 [Member]
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Anticipated impact of adopting result in immaterial increase to assets and liabilities	1.00%
Noncompete Agreements [Member]
Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Line Items]
Intangible asset amortization expense	$ 3,400	$ 3,400	$ 3,400
Intangible assets, remaining amortization expense, 2019	$ 2,800
Intangible assets, life	24 years