Leases - Maturities of lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Leases [Abstract]
Year 1	$ 35,719
Year 2	35,954
Year 3	32,230
Year 4	27,421
Year 5	18,981
Thereafter	127,745
Total lease payments	278,050
Less: Imputed interest	44,420
Total lease liabilities	233,630
Short-term lease liabilities	30,149
Long-term lease liabilities	203,481
Finance Lease
Year 1	244
Year 2	249
Year 3	254
Year 4	259
Year 5	264
Thereafter	4,222
Total lease payments	5,492
Less: Imputed interest	2,958
Total	2,534	$ 0
Short-term lease liabilities	50
Long-term lease liabilities	2,484
Operating Leases
Year 1	35,475
Year 2	35,705
Year 3	31,976
Year 4	27,162
Year 5	18,717
Thereafter	123,523
Total lease payments	272,558
Less: Imputed interest	41,462
Total	231,096
Short-term lease liabilities	30,099
Long-term lease liabilities	$ 200,997