Receivables - Additional Information (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables past due or deemed uncollectible	$ 22,212,000	$ 19,923,000
Interest-bearing financing fee receivables	76,133,000	81,774,000
Allowance for doubtful accounts receivables	16,386,000	12,882,000	$ 23,540,000	$ 28,777,000
Aggregate carrying amount of non-interest bearing receivables	562,149,000	415,439,000
Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivables	$ 0	$ 0