Annual report pursuant to Section 13 and 15(d)

LONG-TERM DEBT - Interest Rate Swaps (Details)

v3.5.0.2
LONG-TERM DEBT - Interest Rate Swaps (Details) - Interest Rate Swaps - Designated as Hedging Instrument - Cash Flow Hedging - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Debt Instrument [Line Items]    
Pay fixed swaps - notional amount $ 403,125 $ 300,000
Net unrealized loss $ 5,834 $ 3,686
Weighted-average maturity period (years) 3 years 10 months 24 days 3 years 4 months 24 days
Weighted-average received rate (as a percent) 0.53% 0.20%
Weighted-average pay rate (as a percent) 1.26% 1.65%