Fair Value Measurements (Details) (Fair value measurements on recurring basis, USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Level 1
Assets:
Total fair value	$ 85,302	$ 90,877
Level 1 | Cash and money market funds
Assets:
Total fair value	46,740	60,062
Level 1 | Pension plan assets
Assets:
Total fair value	38,562	30,815
Level 2
Assets:
Total fair value	143,449	118,116
Level 2 | Pension plan assets
Assets:
Total fair value	143,449	118,116
Total
Assets:
Total fair value	228,751	208,993
Total | Cash and money market funds
Assets:
Total fair value	46,740	60,062
Total | Pension plan assets
Assets:
Total fair value	$ 182,011	$ 148,931