Receivables - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables past due or deemed uncollectible	$ 42,489,000	$ 22,212,000
Interest-bearing financing fee receivables	63,119,000	76,133,000
Allowance for doubtful accounts receivables	29,662,000	16,386,000	$ 11,230,000	$ 12,882,000
Aggregate carrying amount of non-interest bearing receivables	464,495,000	562,149,000
Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts receivables	$ 0	$ 0