Borrowings - Narrative (Details)								3 Months Ended		6 Months Ended
	Jun. 16, 2021 USD ($)	May 28, 2021 USD ($)	May 17, 2021 USD ($)	May 27, 2020 USD ($)	Apr. 29, 2020 USD ($)	May 31, 2019 USD ($)	Jun. 23, 2015 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 13, 2016 USD ($)
Line of Credit Facility [Line Items]
Less unaccreted debt discount								$ 1,423,000		$ 1,423,000		$ 949,000
Interest										17,157,000	$ 16,089,000
Revolving Facility
Line of Credit Facility [Line Items]
Debt instrument, term							5 years
Borrowing capacity						$ 800,000,000	$ 700,000,000
Extension period						1 year
Debt outstanding								0		0
Letters of Credit Outstanding, Amount								7,200,000		7,200,000
Amount available to borrow								$ 792,800,000		$ 792,800,000
For 12 Months in Connection with Certain Acquisitions
Line of Credit Facility [Line Items]
Leverage ratio										4.00
Minimum
Line of Credit Facility [Line Items]
Required percent for prepayment amount of aggregate principal amount													5.00%
Minimum | Revolving Facility
Line of Credit Facility [Line Items]
Applicable leverage ratio								0.00%		0.00%
Maximum | Revolving Facility
Line of Credit Facility [Line Items]
Aggregate lending commitments						$ 400,000,000
Applicable leverage ratio								1.275%		1.275%
Revolving Facility | Minimum
Line of Credit Facility [Line Items]
Interest coverage ratio								3.0		3.0
Revolving Facility | Maximum
Line of Credit Facility [Line Items]
Leverage ratio										3.50
Senior Notes | Maximum
Line of Credit Facility [Line Items]
Limitation of outstanding principal of higher preference debt as percent of consolidated assets								15.00%		15.00%
Senior Notes | 2.625% Senior Notes, due June 2031
Line of Credit Facility [Line Items]
Face amount of debt		$ 500,000,000.0
Stated interest rate			2.625%					2.625%		2.625%
Proceeds from debt, net		494,800,000
Less unaccreted debt discount		600,000
Underwriting commission		(3,300,000)
Offering expenses		(1,300,000)
Redemption price, percentage			101.00%
Senior Notes | 2.625% Senior Notes, due June 2031 | Minimum
Line of Credit Facility [Line Items]
Percent of notes held								25.00%		25.00%
Senior Notes | 4.20% Senior Notes, due December 2021
Line of Credit Facility [Line Items]
Stated interest rate								4.20%		4.20%		4.20%
Extinguishment of debt		$ 350,000,000.0	$ 350,000,000.0
Redemption premium			6,700,000
Amount to be recognized from hedged transactions within 12 months, approximate	$ 1,300,000
Write off of deferred debt issuance cost			100,000
Write off of debt remaining discount			100,000
Write off deferred taxes			$ 400,000
Loss on early debt redemption								$ 8,600,000		$ 8,600,000
Senior Notes | 3.00% Senior Notes, due May 2030
Line of Credit Facility [Line Items]
Face amount of debt					$ 500,000,000.0
Stated interest rate					3.00%			3.00%		3.00%
Proceeds from debt, net					$ 494,400,000
Less unaccreted debt discount					900,000
Underwriting commission					(3,300,000)
Offering expenses					$ (1,400,000)
Redemption price, percentage					101.00%
Senior Notes | 3.00% Senior Notes, due May 2030 | Minimum
Line of Credit Facility [Line Items]
Percent of outstanding amount owned for decision making					25.00%
Senior Notes | 4.5% Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				4.50%	4.50%			4.50%		4.50%
Extinguishment of debt				$ 300,000,000.0	$ 300,000,000.0
Redemption premium				6,800,000
Interest				6,100,000
Amount to be recognized from hedged transactions within 12 months, approximate				1,400,000
Write off of deferred debt issuance cost				100,000
Write off of debt remaining discount				$ 100,000
Loss on early debt redemption									$ 8,400,000		$ 8,400,000
Senior Notes | 3.20% Senior Notes, due June 2023
Line of Credit Facility [Line Items]
Face amount of debt													$ 100,000,000
Stated interest rate								3.20%		3.20%		3.20%	3.20%
Senior Notes | 3.37% Senior Notes, due June 2025
Line of Credit Facility [Line Items]
Face amount of debt													$ 100,000,000
Stated interest rate								3.37%		3.37%		3.37%	3.37%
Letters of Credit | Revolving Facility
Line of Credit Facility [Line Items]
Borrowing capacity						75,000,000
Swing Line Loans | Revolving Facility
Line of Credit Facility [Line Items]
Borrowing capacity						$ 50,000,000