Restructuring and Other Charges (Narrative) (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2019 USD ($) employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	$ 51,100	$ (1,003)	$ 7,942
Payments for restructuring	24,721	2,756	37,074
Restructuring Reserve	31,086	2,415	6,244	$ 36,608
Depreciation	26,700	29,400	28,000
Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	32,908	(494)	5,569
Payments for restructuring	9,319	1,509	2,005
Restructuring Reserve	30,788	2,415	4,508	1,431
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	15,704	(509)	2,373
Payments for restructuring	15,402	1,247	35,069
Restructuring Reserve	298	0	1,736	$ 35,177
2016 and 2019 Restructuring Plans [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	48,612
Prior Headquarters Relocation Charge [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	2,500
Prior Year Plans [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	200
Restructuring Plan 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)		(200)	8,200
Payments for restructuring	1,100	2,600	36,400
Restructuring Reserve		2,400
Prior Headquarters [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	32,700
Depreciation	1,900	4,800
Payments for Rent	600
Restructuring Plan 2015 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)		(800)	(300)
Payments for restructuring		200	$ 700
Restructuring Plan 2019 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	23,600
Restructuring Plan 2019 [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credit)	$ 15,700
Number of positions eliminated | employee	240
Gross, Excluding Sublease Income [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 38,400
Sublease Income Committed [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	3,900
Sublease Income Estimated Uncommitted [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	3,700
Other Current Liabilities [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	11,900	1,500
Other Noncurrent Liabilities [Member] | Facility Closures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 18,900	$ 900