Stockholders' Equity of the Company - Narrative (Details) - USD ($)			1 Months Ended			12 Months Ended
	Mar. 25, 2020	Feb. 18, 2020	Mar. 31, 2020	Jul. 31, 2019	Aug. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 19, 2020	May 18, 2020	Jun. 30, 2018
Class of Stock [Line Items]
Common stock, authorized (shares)						280,000,000	150,000,000		280,000,000	150,000,000
Common stock, value, issued						$ 1,160,000	$ 1,060,000
Aggregate net proceeds after selling commissions						$ 721,665,000	$ 353,722,000	$ 130,693,000
Sale of stock, shares issued (in shares)						116,035,827	106,016,287
Stock repurchase program, number of shares authorized to be repurchased						4,935,826
Stock repurchased during period (in shares)						0	0	0
2014 At-The-Market Program [Member]
Class of Stock [Line Items]
Aggregate gross proceeds								$ 300,000,000.0
2018 At-The-Market Program [Member]
Class of Stock [Line Items]
Aggregate gross proceeds											$ 500,000,000.0
Issuance of Equity under ATM Program [Member]
Class of Stock [Line Items]
Aggregate net proceeds after selling commissions						$ 247,300,000		132,100,000
Aggregate gross proceeds						$ 252,000,000.0		$ 133,800,000
Shares issued, price per share (in dollars per share)						$ 80.08		$ 73.64
Forward Equity Offering [Member]
Class of Stock [Line Items]
Common stock, value, issued		$ 494,500,000			$ 360,500,000
Stock issued, price per share (in dollar per share)		$ 86.00			$ 72.10
Aggregate net proceeds after selling commissions				$ 354,300,000
Forward Equity Offering [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock issued (in shares)		5,750,000		5,000,000	5,000,000
Aggregate net proceeds after selling commissions	$ 474,900,000			$ 354,300,000
Sale of stock, shares issued (in shares)	5,750,000		5,750,000	5,000,000
Forward Equity Offering [Member] | Common Stock [Member] | 2014 At-The-Market Program [Member]
Class of Stock [Line Items]
Sale of stock, shares available for sale (in shares)								1,369,729
Forward Equity Offering [Member] | Common Stock [Member] | 2018 At-The-Market Program [Member]
Class of Stock [Line Items]
Stock issued, price per share (in dollar per share)							$ 80.08
Sale of stock, shares available for sale (in shares)							3,147,110	447,466
Sale of stock, shares issued (in shares)						3,594,576
Sale of stock, available for sale under program						$ 214,200,000
Forward Equity Offering [Member] | Common Stock [Member] | Issuance of Equity under ATM Program [Member]
Class of Stock [Line Items]
Aggregate net proceeds after selling commissions			$ 247,300,000			$ 247,300,000
Sale of stock, shares issued (in shares)			3,147,110