Guarantors - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Condensed Consolidating Balance Sheets
Total investment in real estate, net	$ 4,791.4	$ 4,710.3
Cash and cash equivalents	57.3	76.4
Investment in subsidiaries	0.0	0.0
Rent and other receivables, net	305.3	291.9
Restricted cash	1.3	1.3
Operating lease right-of-use assets, net	208.6	161.9
Intercompany receivable	0.0	0.0
Equity investments	153.1	135.1
Goodwill	455.1	455.1
Intangible assets, net	184.5	196.1
Other assets	121.9	113.9
Total assets	6,278.5	6,142.0
Debt	3,047.0	2,886.6
Operating lease liabilities	243.0	195.8
Construction costs payable	183.4	176.3	$ 155.5
Accounts payable and accrued expenses	121.0	122.7
Intercompany payable	0.0	0.0
Finance lease liabilities	29.4	31.8
Dividends payable	58.7	58.6	51.5
Deferred revenue and prepaid rents	167.3	163.7
Deferred tax liability	57.0	60.5
Other liabilities	7.9	11.4
Total liabilities	3,914.7	3,707.4
Total stockholders' equity	2,363.8	2,434.6	$ 2,378.1	$ 2,226.0
Total liabilities and equity	6,278.5	6,142.0
Eliminations/Consolidations
Condensed Consolidating Balance Sheets
Total investment in real estate, net	75.9	69.9
Cash and cash equivalents	0.0	0.0
Investment in subsidiaries	(6,029.4)	(5,988.0)
Rent and other receivables, net	0.0	0.0
Restricted cash	0.0	0.0
Operating lease right-of-use assets, net	0.0	0.0
Intercompany receivable	(1,788.8)	(1,813.2)
Equity investments	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other assets	0.0	0.0
Total assets	(7,742.3)	(7,731.3)
Debt	0.0	0.0
Operating lease liabilities	0.0	0.0
Construction costs payable	0.0	0.0
Accounts payable and accrued expenses	0.0	0.0
Intercompany payable	(1,788.8)	(1,813.2)
Finance lease liabilities	0.0	0.0
Dividends payable	0.0	0.0
Deferred revenue and prepaid rents	0.0	0.0
Deferred tax liability	0.0	0.0
Other liabilities	0.0	0.0
Total liabilities	(1,788.8)	(1,813.2)
Total stockholders' equity	(5,953.5)	(5,918.1)
Total liabilities and equity	(7,742.3)	(7,731.3)
General Partner
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0.0	0.0
Cash and cash equivalents	0.0	0.0
Investment in subsidiaries	16.4	16.8
Rent and other receivables, net	0.0	0.0
Restricted cash	0.0	0.0
Operating lease right-of-use assets, net	0.0	0.0
Intercompany receivable	0.0	0.0
Equity investments	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other assets	0.0	0.0
Total assets	16.4	16.8
Debt	0.0	0.0
Operating lease liabilities	0.0	0.0
Construction costs payable	0.0	0.0
Accounts payable and accrued expenses	0.0	0.0
Intercompany payable	0.0	0.0
Finance lease liabilities	0.0	0.0
Dividends payable	0.0	0.0
Deferred revenue and prepaid rents	0.0	0.0
Deferred tax liability	0.0	0.0
Other liabilities	0.0	0.0
Total liabilities	0.0	0.0
Total stockholders' equity	16.4	16.8
Total liabilities and equity	16.4	16.8
Parent Guarantor
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0.0	0.0
Cash and cash equivalents	0.2	0.0
Investment in subsidiaries	2,329.8	2,402.2
Rent and other receivables, net	0.0	0.0
Restricted cash	0.0	0.0
Operating lease right-of-use assets, net	0.0	0.0
Intercompany receivable	16.6	21.1
Equity investments	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other assets	0.0	0.0
Total assets	2,346.6	2,423.3
Debt	0.0	0.0
Operating lease liabilities	0.0	0.0
Construction costs payable	0.0	0.0
Accounts payable and accrued expenses	0.0	0.0
Intercompany payable	0.0	0.0
Finance lease liabilities	0.0	0.0
Dividends payable	58.7	58.6
Deferred revenue and prepaid rents	0.0	0.0
Deferred tax liability	0.0	0.0
Other liabilities	0.0	0.0
Total liabilities	58.7	58.6
Total stockholders' equity	2,287.9	2,364.7
Total liabilities and equity	2,346.6	2,423.3
LP Co-issuer
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0.0	0.0
Cash and cash equivalents	0.4	0.6
Investment in subsidiaries	3,683.2	3,569.0
Rent and other receivables, net	0.0	0.0
Restricted cash	0.0	0.0
Operating lease right-of-use assets, net	0.0	0.0
Intercompany receivable	1,733.3	1,753.3
Equity investments	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other assets	0.6	3.5
Total assets	5,417.5	5,326.4
Debt	3,047.0	2,886.6
Operating lease liabilities	0.0	0.0
Construction costs payable	0.0	0.0
Accounts payable and accrued expenses	16.2	5.1
Intercompany payable	16.6	21.1
Finance lease liabilities	0.0	0.0
Dividends payable	0.0	0.0
Deferred revenue and prepaid rents	0.0	0.0
Deferred tax liability	0.0	0.0
Other liabilities	7.9	11.4
Total liabilities	3,087.7	2,924.2
Total stockholders' equity	2,329.8	2,402.2
Total liabilities and equity	5,417.5	5,326.4
Finance Co-issuer
Condensed Consolidating Balance Sheets
Total investment in real estate, net	0.0	0.0
Cash and cash equivalents	0.0	0.0
Investment in subsidiaries	0.0	0.0
Rent and other receivables, net	0.0	0.0
Restricted cash	0.0	0.0
Operating lease right-of-use assets, net	0.0	0.0
Intercompany receivable	0.0	0.0
Equity investments	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other assets	0.0	0.0
Total assets	0.0	0.0
Debt	0.0	0.0
Operating lease liabilities	0.0	0.0
Construction costs payable	0.0	0.0
Accounts payable and accrued expenses	0.0	0.0
Intercompany payable	0.0	0.0
Finance lease liabilities	0.0	0.0
Dividends payable	0.0	0.0
Deferred revenue and prepaid rents	0.0	0.0
Deferred tax liability	0.0	0.0
Other liabilities	0.0	0.0
Total liabilities	0.0	0.0
Total stockholders' equity	0.0	0.0
Total liabilities and equity	0.0	0.0
Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Total investment in real estate, net	4,715.5	4,640.4
Cash and cash equivalents	56.7	75.8
Investment in subsidiaries	0.0	0.0
Rent and other receivables, net	305.3	291.9
Restricted cash	1.3	1.3
Operating lease right-of-use assets, net	208.6	161.9
Intercompany receivable	38.9	38.8
Equity investments	153.1	135.1
Goodwill	455.1	455.1
Intangible assets, net	184.5	196.1
Other assets	121.3	110.4
Total assets	6,240.3	6,106.8
Debt	0.0	0.0
Operating lease liabilities	243.0	195.8
Construction costs payable	183.4	176.3
Accounts payable and accrued expenses	104.8	117.6
Intercompany payable	1,772.2	1,792.1
Finance lease liabilities	29.4	31.8
Dividends payable	0.0	0.0
Deferred revenue and prepaid rents	167.3	163.7
Deferred tax liability	57.0	60.5
Other liabilities	0.0	0.0
Total liabilities	2,557.1	2,537.8
Total stockholders' equity	3,683.2	3,569.0
Total liabilities and equity	$ 6,240.3	$ 6,106.8