Stockholders' Equity - Additional Information (Details)					1 Months Ended					3 Months Ended	9 Months Ended
	Jul. 15, 2020 day	Jul. 06, 2020	Dec. 28, 2018 shares	Feb. 14, 2017 day $ / shares shares	Apr. 15, 2019 shares	Apr. 30, 2018 USD ($) shares	Mar. 31, 2017 USD ($) shares	Nov. 30, 2015 day $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) day $ / shares shares	Sep. 30, 2019 shares	Dec. 31, 2019 USD ($) shares	Nov. 15, 2018 USD ($)
Stockholders' Equity (Textual)
Common stock transactions between shareholders (in shares) | shares					3,952,155
Stock repurchase program, authorized amount														$ 1,500,000
Preferred stock, dividend rate, percentage		7.50%
Common stock, outstanding (in shares) | shares										33,094,664	33,094,664		33,033,793
Convertible units, automatic exchange, number of trading days | day	20
Preferred return prior to initial public offering, numerator, basis spread over CPI											0.50%
Preferred return after initial public offering, numerator, basis spread over CPI											0.75%
Preferred return, numerator, basis spread over effective income tax rate											1.00%
Investment in life insurance policies, at fair value										$ 787,260,000	$ 787,260,000		$ 796,039,000
Eliminations | Preferred Series C Unit Accounts
Stockholders' Equity (Textual)
Investment in life insurance policies, at fair value										$ 161,000,000.0	$ 161,000,000.0
Ben LP | Eliminations
Stockholders' Equity (Textual)
Investment (in shares) | shares										46,887,963	46,887,963		42,171,946
Common Stock
Stockholders' Equity (Textual)
Issuance of common stock (in shares) | shares			27,013,516						800,000	57,183	60,871	58,009
Common stock, par value (in usd per share) | $ / shares									$ 12.50
Net proceeds									$ 8,600,000
BCH
Stockholders' Equity (Textual)
Annualized return required											1.00%
Quarterly preferred return cap, percent, threshold one											0.25%
Quarterly preferred return cap, percent, threshold two											0.50%
Quarterly preferred return cap, percent, threshold three											0.75%
Quarterly preferred return cap, percent, threshold four											1.00%
Quarterly preferred return cap, percent, threshold five											1.25%
Quarterly preferred return cap, revenue, threshold one											$ 80,000,000
Quarterly preferred return cap, revenue, threshold two, minimum											80,000,000
Quarterly preferred return cap, revenue, threshold three, minimum											105,000,000
Quarterly preferred return cap, revenue, threshold four, minimum											125,000,000
Quarterly preferred return cap, revenue, threshold five, minimum											135,000,000
Quarterly preferred return cap, revenue, threshold two, maximum											105,000,000
Quarterly preferred return cap, revenue, threshold three, maximum											125,000,000
Quarterly preferred return cap, revenue, threshold four, maximum											135,000,000
Quarterly preferred return cap, revenue, threshold five, maximum											140,000,000
Quarterly preferred return cap, revenue, threshold six											$ 140,000,000
Preferred return prior to initial public offering, numerator, basis spread over CPI											2.00%
Preferred return after initial public offering, numerator, basis spread over CPI											3.00%
Preferred return, numerator, basis spread over effective income tax rate											1.00%
Sub-capital accounts, percentage											20.00%
Limit on indebtedness, capital percent of NAV threshold										55.00%	55.00%
Limit on indebtedness, debt percent of NAV threshold										40.00%	40.00%
Ben LP
Stockholders' Equity (Textual)
Common stock, outstanding (in shares) | shares										48,749,630	48,749,630		44,146,623
Capital contributions permitted (in usd per share) | $ / shares										$ 10	$ 10
Convertible units, automatic exchange, number of trading days | day											20
Common Stock
Stockholders' Equity (Textual)
Issuance of common stock (in shares) | shares			27,013,516
Common Stock | BCC
Stockholders' Equity (Textual)
Common stock transactions between shareholders (in shares) | shares			2,500,000
Common Stock | AltiVerse
Stockholders' Equity (Textual)
Common stock transactions between shareholders (in shares) | shares			1,452,155
Redeemable Preferred Stock
Stockholders' Equity (Textual)
Preferred stock, authorized (in shares) | shares								100,000
Preferred stock, par value (in usd per share) | $ / shares								$ 1,000
Preferred stock, dividend rate, percentage								7.00%
Preferred stock, liquidation preference per share (in usd per share) | $ / shares								$ 1,000
Debt instrument, convertible, threshold trading days | day								20
Debt instrument, convertible, conversion price (in usd per share) | $ / shares								$ 15.00
Preferred stock redemption, percentage								15.00%
Issuance of preferred stock (in shares) | shares							99,127
Proceeds from (repurchase of) redeemable preferred stock							$ 99,100,000
Payments of stock issuance costs							$ 7,000,000.0
Series 2 Redeemable Preferred Stock
Stockholders' Equity (Textual)
Preferred stock, authorized (in shares) | shares				150,000
Preferred stock, liquidation preference per share (in usd per share) | $ / shares				$ 1,000
Debt instrument, convertible, threshold trading days | day				20
Debt instrument, convertible, conversion price (in usd per share) | $ / shares				$ 12.75
Preferred stock redemption, percentage				10.00%
Issuance of preferred stock (in shares) | shares						149,979
Payments of stock issuance costs						$ 10,300,000
Preferred stock redemption price											107.00%
Aggregate gross consideration						$ 150,000,000.0
Series A Preferred Stock | BCH
Stockholders' Equity (Textual)
Income allocation percentage											50.00%
Class A and S units | BCH
Stockholders' Equity (Textual)
Income allocation percentage											50.00%
Class S Ordinary | BCH
Stockholders' Equity (Textual)
Preferred units issued (in shares) | shares										5,700,000	5,700,000		5,700,000
Preferred units outstanding (in shares) | shares										5,700,000	5,700,000		5,700,000
Common stock exchange ratio										1	1
Class S Preferred Units
Stockholders' Equity (Textual)
Preferred return, numerator, basis spread over effective income tax rate											1.00%
Common stock exchange ratio										1.2	1.2
Preferred return, annualized revenue threshold											$ 140,000,000
Preferred return, numerator, basis spread over CPI											0.75%