Fair Value Measurements - Schedule of changes in level 3 assets and liabilities (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of year - assets	$ 13,800,000	$ 14,800,000
Balance at beginning of year - liabilities	(97,700,000)	0
Acquisitions - assets	0	0
Acquisitions - liabilities	0	(93,600,000)
Purchases - assets	100,000	1,200,000
Purchases - liabilities	0	0
Sales - assets	(700,000)	(1,600,000)
Sales - liabilities	0	0
Settlements - assets	(2,100,000)	(2,400,000)
Settlements - liabilities	6,300,000	4,100,000
Transfers out of Level 3 - assets	0	(200,000)
Transfers out of Level 3 - liabilities	0	0
Balance at End of Year - assets	14,000,000	13,800,000
Balance at End of Year - liabilities	(98,500,000)	(97,700,000)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in unrealized gains (losses) included in net income relating to assets and liabilities held at the end of the year	1,200,000	1,300,000
Contingent Consideration Liability [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in unrealized gains (losses) included in net income relating to assets and liabilities held at the end of the year	(7,100,000)	(8,200,000)
Investment and other income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses) - assets	2,900,000	2,000,000
Total realized and unrealized gains (losses) - liabilities	0	0
General, administrative and other expense [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses) - assets	0	0
Total realized and unrealized gains (losses) - liabilities	(6,700,000)	(7,700,000)
Other Income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses) - assets	0	0
Total realized and unrealized gains (losses) - liabilities	$ (400,000)	$ (500,000)