Basis of Presentation of Interim Period Statements - Schedule of Reconciles of Cash, Cash Equivalents and Restricted Cash Balances (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 14,272	$ 44,570	$ 38,223	$ 35,371
Restricted cash, included in restricted cash and investments	262,550	228,771	158,333	105,331
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 276,822	$ 273,341	$ 196,556	$ 140,702