Fair Value Measurements - Additional Information (Detail) - USD ($) |
Sep. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Fair Value Disclosures [Abstract] | ||
| Receivables sold to Investors | $ 414,200,000 | $ 360,300,000 |
| Assets measured at fair value on a nonrecurring basis | 0 | |
| Liabilities measured at fair value on a nonrecurring basis | $ 0 |