Equity and Capital Equity and Capital - Common Stock (Details) - USD ($)			1 Months Ended	9 Months Ended
	Feb. 05, 2019	Jan. 31, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Class of Stock [Line Items]
Common stock remaining available for Issuance			500,000,000.0	500,000,000.0
Stock Repurchased and Retired During Period, Value				$ (32,777,000)	$ (124,989,000)
Stock Repurchase Program, Authorized Amount	$ 250,000,000
Stock Repurchase Program Expiration Date	Feb. 04, 2020
Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares		563,229
Stock Repurchased and Retired During Period, Value		$ (32,800,000)		(5,000)	$ (21,000)
Common Stock [Member] | Average share price [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Value Per Share		$ (58.17)
Accumulated Other Comprehensive Income (Loss) [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Value				$ 0
ATM Equity Offering Program [Member]
Class of Stock [Line Items]
Shares issued under program					0
ATM Equity Offering Program [Member] | Forward Equity Offering [Member]
Class of Stock [Line Items]
Number of shares issuable			1,894,845
Sale of stock, average offering price			$ 67.99	$ 67.99
Settlement date			Sep. 12, 2020
Number of shares settled				0
Maximum [Member]
Class of Stock [Line Items]
Equity Issuances, Common Shares Authorized for Issuance			500,000,000	500,000,000