Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Equity:
Preferred stock, par value (in USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Equity:
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	172,399,000	170,555,000
Common stock, shares outstanding (in shares)	172,399,000	170,555,000
Class B Common Stock
Equity:
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	1,001,000	1,010,000
Common stock, shares outstanding (in shares)	1,001,000	1,010,000
Private Perpetual Preferred Units, Series 2019
Equity:
Private perpetual preferred units, per unit liquidation preference (in USD per share)	$ 13.52	$ 13.52
Private perpetual preferred units, issued (in shares)	4,664,038	4,664,000
Private perpetual preferred units, outstanding (in shares)	4,664,000	4,664,000
Private Perpetual Preferred Units, Series 2014
Equity:
Private perpetual preferred units, per unit liquidation preference (in USD per share)	$ 16.62	$ 16.62
Private perpetual preferred units, issued (in shares)	1,560,000	1,560,000
Private perpetual preferred units, outstanding (in shares)	1,560,000	1,560,000