Significant Accounting Policies - Additional Information (Detail) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 25, 2015	Feb. 10, 2014	May 22, 2012
Significant Accounting Policies [Line Items]
Plan Effective Date		Mar. 19, 2012
Unearned premiums		$ 39,000	$ 270,000
Premium deficiency reserves		300,000	300,000
Other liabilities		16,303,000	14,063,000
Accrued professional fees		4,700,000	$ 1,100,000
Comprehensive income (loss)		$ 0
Income tax at the federal statutory rate		35.00%	35.00%	35.00%
Amount of dividends paid on or after Effective Date		$ 0
Preferred stock dividends declared		18,050,000	$ 18,000,000	$ 17,748,000
Preferred stock dividends paid		18,050,000	18,000,000	16,998,000
Scenario Forecast [Member]
Significant Accounting Policies [Line Items]
Income tax at the federal statutory rate	21.00%
2012 Plan [Member]
Significant Accounting Policies [Line Items]
Common stock reserved for future issuance					12.0	3.0	2.0
Redeemable Convertible Series B Preferred Stock [Member]
Significant Accounting Policies [Line Items]
Accrued fees		10,800,000	12,300,000
Accrued dividends		800,000	700,000
Preferred stock dividends declared		18,000,000	18,000,000	17,000,000
Additional accrued preferred stock dividends		800,000	700,000	700,000
Preferred stock dividends paid		$ 18,000,000	$ 18,000,000	$ 17,000,000
Preferred stock dividend rate		3.00%	3.00%	3.00%