Equity Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	670,000,000	670,000,000
Proceeds from issuance from common stock	$ 72,539	$ (919)	$ 89,055
General partner ownership interest	96.60%	96.60%
Redemption value of operating partnership units outstanding	$ 692,500	$ 565,300
ATM Program, 2018
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	826,600,000			900,000,000.0
Sale of common stock, net (in shares)	228,271
Share issued, price per share (in dollars per share)	$ 321.56
Proceeds from issuance from common stock	$ 73,400
ATM Program, 2016
Class of Stock [Line Items]
Sale of common stock, net (in shares)			345,444
Share issued, price per share (in dollars per share)			$ 260.38
Proceeds from issuance from common stock			$ 89,900
Operating Partnership Units
Class of Stock [Line Items]
Number of shares outstanding	2,158,396	2,171,309
Long Term Incentive Plan 2014 Units
Class of Stock [Line Items]
Number of shares outstanding	143,257	134,080