Redeemable Preferred Stock (Details)			12 Months Ended
	Nov. 24, 2020 $ / shares shares	Feb. 14, 2020 USD ($) warrant $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares
Class of Stock [Line Items]
gross potential offering proceeds			$ 1,125,000,000
Common Stock, Dividends, Per Share, Declared | $ / shares			$ 0.7875	$ 1.05	$ 1.02
Proceeds from Other Equity			$ 323,722,000
daycountvolweightedavgcalcformarketvalue			20
aggregate offering costs			$ 36,815,000
prorataamountofferingcostsreclassed			6,889,000
deferred offering costs not yet reclassified			$ 2,408,000
maximum shares available to be issued | shares		1,500,000
shares common stock from warrant exercises | shares		20	20
Deferred offering costs			$ 9,297,000
specifically identifiable offering costs			27,518,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.01
Dividends, Common Stock, Cash			$ 37,143,000	$ 38,868,000	$ 46,755,000
Redemption Percent			100.00%
Gross Proceeds Reimbursement Percent			2.00%
Consideration received on transaction		$ 1,500,000,000
Number Of Warrants For Each Equity Offering Unit | warrant		1
A1M1 Offering [Member]
Class of Stock [Line Items]
Shares Issued, Price Per Share | $ / shares			$ 1,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage			6.00%
preferred stock | shares			2,226,000	2,226,000
Preferred Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01
Preferred Stock, Value, Issued			$ 13,000	$ 17,000
Shares called during the period | shares	208,786
Redemption price per share (usd per share) | $ / shares	$ 1,000
Number Of Equity Instruments Called By Equity Offering Unit | shares		1
A1 Preferred Stock [Member]
Class of Stock [Line Items]
Shares Issued, Price Per Share | $ / shares			$ 1,000
Redemption Fee Percent			13.00%
Redemption Fee Percent, After Year One			10.00%
Redemption Fee Percent, After Year Two			5.00%
Preferred Share Dividend Percent			6.00%
Redemption Percent			100.00%
M1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Share Dividend Percent			6.10%
Dividend Rate, Annual Increase			0.10%
M1 Preferred Stock [Member] | Maximum [Member]
Class of Stock [Line Items]
Preferred Share Dividend Percent			7.10%
Dealer Manager Fees, Percent			12.00%
2019 Shelf Offering [Member] [Domain]
Class of Stock [Line Items]
gross potential offering proceeds			$ 125,000,000
Proceeds from Other Equity			33,199,000
aggregate offering costs			1,829,000
prorataamountofferingcostsreclassed			531,000
deferred offering costs not yet reclassified			777,000
Deferred offering costs			1,308,000
specifically identifiable offering costs			521,000
2019 ATM Offering [Member] [Domain]
Class of Stock [Line Items]
Consideration received on transaction			125,000,000
A1M1 Offering [Domain]
Class of Stock [Line Items]
gross potential offering proceeds			1,000,000,000
Proceeds from Other Equity			290,523,000
aggregate offering costs			34,986,000
prorataamountofferingcostsreclassed			6,358,000
deferred offering costs not yet reclassified			$ 1,631,000
maximum shares available to be issued | shares			1,000,000
Deferred offering costs			$ 7,989,000
specifically identifiable offering costs			$ 26,997,000
$1.5 billion unit [Domain]
Class of Stock [Line Items]
maximum shares available to be issued | shares			1,500,000,000