Accumulated Other Comprehensive Loss - Summary of the Tax Effects Allocated to Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Loss
Reclassification adjustment for loss (gain) included in earnings, Before-tax-amount			$ (28)	$ 2	$ 1,050
Reclassification of other-than-temporary impairment loss included in earnings, Before-tax-amount					63
Reclassification into retained earnings for the adoption of ASU, Before-tax-amount	[1]				932
Total before income taxes		$ (2)	293	810	1,554
Other comprehensive loss, Tax (expense) or benefit	[2]		(74)	(206)	(706)
Total other comprehensive (loss) income, net of tax		(2)	219	604	848
Unrealized (loss) gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain (loss) on investments, Net-of-tax amount				602
Reclassification adjustment for loss (gain) included in earnings, Before-tax-amount			(28)	2	1,050
Reclassification adjustment for loss (gain) included in earnings, Tax (expense) or benefit			7		(266)
Reclassification adjustment for loss (gain) included in earnings, Net-of-tax amount			(21)	2	784
Reclassification of other-than-temporary impairment loss included in earnings, Before-tax-amount					63
Reclassification adjustment for other-than-temporary impairment loss included in earnings, Tax (expense) or benefit					(16)
Reclassification adjustment for other-than-temporary impairment loss included in earnings, Net-of-tax amount					47
Total before income taxes		(2)	293	810	1,554
Other comprehensive loss, Tax (expense) or benefit			(74)	(206)	(706)
Total other comprehensive (loss) income, net of tax		(2)	219	604	848
Unrealized (loss) gain on available for sale securities | ASU 2016-01
Accumulated Other Comprehensive Loss
Reclassification into retained earnings for the adoption of ASU, Before-tax-amount					932
Reclassification into retained earnings for the adoption of ASU, Tax (expense) or benefit					(236)
Reclassification into retained earnings for the adoption of ASU, Net-of-tax amount					696
Unrealized (loss) gain on available for sale securities | ASU 2018-02
Accumulated Other Comprehensive Loss
Reclassification into retained earnings for the adoption of ASU, Tax (expense) or benefit					(313)
Reclassification into retained earnings for the adoption of ASU, Net-of-tax amount					(313)
Unrestricted available-for-sale, Debt securities | Unrealized (loss) gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain (loss) on investments, Before-tax amount		(9)	321	790	(482)
Unrealized gain (loss) on investments, Tax (expense) or benefit		2	(81)	(201)	123
Unrealized gain (loss) on investments, Net-of-tax amount		(7)	$ 240	589	(359)
Restricted | Unrealized (loss) gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain (loss) on investments, Before-tax amount		7		18	(9)
Unrealized gain (loss) on investments, Tax (expense) or benefit		(2)		(5)	2
Unrealized gain (loss) on investments, Net-of-tax amount		$ 5		$ 13	$ (7)

[1] The reclassification into retained earnings for the six months ended June 30, 2018 relates to the adoption of Accounting Standards Update (“ASU”) 201601 Financial Instruments - Overall, as amended (“ASU 201601”). The new guidance was effective January 1, 2018, and required equity investments to be measured at fair value with changes in fair value recognized in results of operations rather than the condensed consolidated statements of comprehensive income.Income tax expense for the six months ended June 30, 2018

[2] Income tax expense for the six months ended June 30, 2018 includes $0.3 million of income tax expense related to the adoption of ASU 201802 Income Statement - Reporting Comprehensive Income (“ASU 201802”). The new guidance was effective January 1, 2018, and allowed a reclassification from accumulated other comprehensive loss to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act (the “Tax Act”).