Public Offering	12 Months Ended
Dec. 31, 2019
Public Offering [Abstract]
Public Offering	3. Public Offering In November 2017, the Company closed its Public Offering of 34,500,000 units at a price of $10.00 per unit (the "Units"), with gross proceeds of $345,000,000 from the sale of Units. The closings occurred on November 7, 2017 with respect to 30,000,000 Units and on November 9, 2017 with respect to 4,500,000 Units related to the exercise of the underwriters' overallotment option. Each Unit consists of one share of Class A common stock, $0.0001 par value, and one-third of one warrant (each, a "Public Warrant" and, collectively, the "Public Warrants"). Each whole Public Warrant entitles the holder to purchase one share of Class A common stock at a price of $11.50 per share. No fractional shares will be issued upon separation of the Units and only whole Public Warrants trade. Each Public Warrant will become exercisable on the later of 30 days after the completion of the Company's initial business combination or 12 months from the closing of the Public Offering and will expire five years after the completion of the Company's initial business combination or earlier upon redemption or liquidation. Once the Public Warrants become exercisable, the Company may redeem the outstanding Public Warrants in whole and not in part at a price of $0.01 per Public Warrant upon a minimum of 30 days' prior written notice of redemption, if and only if the last sale price of the Company's Class A common stock equals or exceeds $18.00 per share for any 20 trading days within a 30-trading day period ending on the third trading day prior to the date on which the Company sent the notice of redemption to the Public Warrant holders. During the liquidation period the Company and the holders of its Public Warrants executed an amendment to the Warrant Agreement, dated as of November 2, 2017 (the "Warrant Agreement"), between the Company and Continental Stock Transfer & Trust Company, to automatically convert each of the Company's 11,500,000 outstanding Public Warrants into the right to receive $0.02 per whole Public Warrant, payable in cash. In December 2019, the Company paid $225,990 to its warrant holders in relation to the automatic redemption of the warrants. Simultaneous with the closing of the Public Offering on November 7, 2017, Sentinel Management Holdings, LLC (the "Sponsor") purchased an aggregate of 5,333,333 private placement warrants at a price of $1.50 per whole warrant (approximately $8,000,000 in the aggregate) in a private placement (the "Private Placement Warrants"). Simultaneously with the closing of the overallotment, the Company consummated the private placement of an additional 600,000 Private Placement Warrants to the Sponsor, generating gross proceeds of approximately $900,000. The Company paid an underwriting discount of 2.0% of the per Unit offering price to the underwriters at the closing of the Public Offering, with the Deferred Discount payable upon the Company's completion of an initial business combination. The Deferred Discount was payable to the underwriters from the amounts held in the Trust Account solely in the event the Company completed its initial business combination. In accordance with the terms of the underwriting agreement entered into in connection with the Public Offering, the underwriters forfeited any rights or claims to the Deferred Discount because the Company was unable to consummate an initial business combination by the November 7, 2019 deadline under its Charter.

Public Offering

12 Months Ended

Dec. 31, 2019

3. Public Offering

In November 2017, the Company closed its Public Offering of 34,500,000 units at a price of $10.00 per unit (the "Units"), with gross proceeds of $345,000,000 from the sale of Units. The closings occurred on November 7, 2017 with respect to 30,000,000 Units and on November 9, 2017 with respect to 4,500,000 Units related to the exercise of the underwriters' overallotment option.

Each Unit consists of one share of Class A common stock, $0.0001 par value, and one-third of one warrant (each, a "Public Warrant" and, collectively, the "Public Warrants"). Each whole Public Warrant entitles the holder to purchase one share of Class A common stock at a price of $11.50 per share. No fractional shares will be issued upon separation of the Units and only whole Public Warrants trade. Each Public Warrant will become exercisable on the later of 30 days after the completion of the Company's initial business combination or 12 months from the closing of the Public Offering and will expire five years after the completion of the Company's initial business combination or earlier upon redemption or liquidation. Once the Public Warrants become exercisable, the Company may redeem the outstanding Public Warrants in whole and not in part at a price of $0.01 per Public Warrant upon a minimum of 30 days' prior written notice of redemption, if and only if the last sale price of the Company's Class A common stock equals or exceeds $18.00 per share for any 20 trading days within a 30-trading day period ending on the third trading day prior to the date on which the Company sent the notice of redemption to the Public Warrant holders.

During the liquidation period the Company and the holders of its Public Warrants executed an amendment to the Warrant Agreement, dated as of November 2, 2017 (the "Warrant Agreement"), between the Company and Continental Stock Transfer & Trust Company, to automatically convert each of the Company's 11,500,000 outstanding Public Warrants into the right to receive $0.02 per whole Public Warrant, payable in cash. In December 2019, the Company paid $225,990 to its warrant holders in relation to the automatic redemption of the warrants.

Simultaneous with the closing of the Public Offering on November 7, 2017, Sentinel Management Holdings, LLC (the "Sponsor") purchased an aggregate of 5,333,333 private placement warrants at a price of $1.50 per whole warrant (approximately $8,000,000 in the aggregate) in a private placement (the "Private Placement Warrants"). Simultaneously with the closing of the overallotment, the Company consummated the private placement of an additional 600,000 Private Placement Warrants to the Sponsor, generating gross proceeds of approximately $900,000.

The Company paid an underwriting discount of 2.0% of the per Unit offering price to the underwriters at the closing of the Public Offering, with the Deferred Discount payable upon the Company's completion of an initial business combination. The Deferred Discount was payable to the underwriters from the amounts held in the Trust Account solely in the event the Company completed its initial business combination. In accordance with the terms of the underwriting agreement entered into in connection with the Public Offering, the underwriters forfeited any rights or claims to the Deferred Discount because the Company was unable to consummate an initial business combination by the November 7, 2019 deadline under its Charter.