Receivables - Additional Information (Detail) - USD ($)	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables past due or deemed uncollectible	$ 37,732,000		$ 42,309,000
Interest-bearing financing fee receivables	77,304,000		90,966,000
Allowance for doubtful accounts receivables	31,288,000	$ 33,535,000	40,164,000	$ 34,524,000	$ 34,956,000	$ 23,746,000
Aggregate carrying amount of non-interest bearing receivables	590,863,000		594,568,000
Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivables	$ 0		$ 0