Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Mar. 31, 2016 |
Sep. 16, 2014 |
Oct. 31, 2011 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Derivative [Line Items] | ||||||
| Payment of interest rate swap | $ 3,114 | $ 1,502 | ||||
| New Interest Rate Swap | ||||||
| Derivative [Line Items] | ||||||
| Notional amount | $ 220,000 | |||||
| Interest rate on notional amount | 2.97% | |||||
| Interest rate swap agreement with bank, agreement period | 3 months | |||||
| Fair value loss | $ 13,000 | 18,700 | ||||
| Three-Year Interest Rate Swap | ||||||
| Derivative [Line Items] | ||||||
| Notional amount | $ 200,000 | |||||
| Interest rate on notional amount | 2.49% | |||||
| Interest rate swap agreement with bank, agreement period | 3 months | |||||
| Fair value loss | $ 500 | |||||
| Term of derivative | 3 years | |||||
| Payment of interest rate swap | $ 500 | |||||
| London Interbank Offered Rate (LIBOR) | Three-Year Interest Rate Swap | Interest Rate Floor | ||||||
| Derivative [Line Items] | ||||||
| Interest rate on LIBOR | 1.50% | |||||