Accumulated Other Comprehensive Loss - Summary of the Tax Effects Allocated to Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Loss
Reclassification adjustment for net gain included in earnings before-tax amount		$ (4)	$ (69)
Reclassification adjustment for net gain included in earnings, Tax (expense) or benefit		1	17
Reclassification adjustment for net gain included in earnings net-of-tax amount		(3)	(52)
Total before income taxes		(1,523)	455	$ 1,472
Other comprehensive loss, Tax (expense) or benefit	[1]	386	(116)	(685)
Total other comprehensive (loss) income, net of tax		(1,137)	339	$ 787
Accumulated Other Comprehensive Loss.
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Net-of-tax amount		(1,134)	391
Reclassification adjustment for net gain included in earnings net-of-tax amount		(3)	(52)
Total other comprehensive (loss) income, net of tax		(1,137)	339
Unrealized (loss) and gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Net-of-tax amount		103	642
Reclassification adjustment for net gain included in earnings net-of-tax amount		(3)	(52)
Total other comprehensive (loss) income, net of tax		100	590
Unrealized loss Cash flow hedge, Interest rate swap
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Net-of-tax amount		(1,237)	(251)
Total other comprehensive (loss) income, net of tax		(1,237)	(251)
Unrealized loss Cash flow hedge, Interest rate swap | Interest rate swap
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Before-tax amount		(836)	(336)
Unrealized gain on investments, Tax (expense) or benefit		212	85
Unrealized gain on investments, Net-of-tax amount		(624)	(251)
Unrealized loss Cash flow hedge, Interest rate swap | Interest rate swap, unconsolidated affiliates
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Before-tax amount		(821)
Unrealized gain on investments, Tax (expense) or benefit		208
Unrealized gain on investments, Net-of-tax amount		(613)
Unrestricted available-for-sale, Debt securities | Unrealized (loss) and gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Before-tax amount		130	842
Unrealized gain on investments, Tax (expense) or benefit		(33)	(214)
Unrealized gain on investments, Net-of-tax amount		97	628
Restricted | Unrealized (loss) and gain on available for sale securities
Accumulated Other Comprehensive Loss
Unrealized gain on investments, Before-tax amount		8	18
Unrealized gain on investments, Tax (expense) or benefit		(2)	(4)
Unrealized gain on investments, Net-of-tax amount		$ 6	$ 14

[1] Income tax benefit (expense) for the year ended December 31, 2018 includes $0.3 million of income tax expense related to the adoption of ASU 2018-02 Income Statement – Reporting Comprehensive Income (“ASU 2018-02”). 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 Act.