Subsequent Events Subsequent Events (Details) - USD ($)		1 Months Ended	2 Months Ended	6 Months Ended
	Apr. 20, 2018	Apr. 30, 2018	Jun. 26, 2018	Mar. 31, 2018	Apr. 01, 2017
Subsequent Event [Line Items]
Borrowings under credit facility				$ 50,000,000	$ 100,000,000
Repayments of Lines of Credit				$ 120,000,000	$ 140,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Borrowings under credit facility		$ 150,000,000
Repayments of Lines of Credit		$ 50,000,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt	$ 100,000,000
Accelerated Share Repurchase Agreement [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Accelerated Share Repurchases, Initial Number of Shares	951,814
Accelerated Share Repurchases, Initial Price Paid Per Share	$ 84.05
Additional Paid-in Capital [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Repurchased and Retired During Period, Value	$ 80,000,000		$ 20,000,000