EQUITY (Common Stock) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Feb. 29, 2020	Dec. 31, 2019	Feb. 28, 2019
Class of Stock [Line Items]
Proceeds from sale of shares	$ 383,800,000
Fees related to stock issuance	$ 500,000
Increase (Decrease) in Stockholders' Equity
Balance (in shares)	115,243,029
Issuance of stock (in shares)	127,330,160
Stock option exercises (in shares)	1,058,722
Vesting of restricted stock awards, net of shares withheld for tax (shares)	2,566,031
Balance (in shares)	247,574,364
AOG
Increase (Decrease) in Stockholders' Equity
Exchanges of AOG Units (in shares)	1,376,422
Class A common stock
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Authorized amount		$ 150,000,000		$ 150,000,000
Remaining available for repurchases of common stock	$ 150,000,000
Increase (Decrease) in Stockholders' Equity
Balance (in shares)	115,242,028
Issuance of stock (in shares)	12,130,540
Stock option exercises (in shares)	1,058,722
Vesting of restricted stock awards, net of shares withheld for tax (shares)	2,566,031
Balance (in shares)	132,373,743
Class A common stock | AOG
Increase (Decrease) in Stockholders' Equity
Exchanges of AOG Units (in shares)	1,376,422
Class A common stock | Underwritten
Class of Stock [Line Items]
Number of shares sold (in shares)	12,130,540
Class B common stock
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01		0.01
Increase (Decrease) in Stockholders' Equity
Balance (in shares)	1,000
Issuance of stock (in shares)	0
Stock option exercises (in shares)	0
Vesting of restricted stock awards, net of shares withheld for tax (shares)	0
Balance (in shares)	1,000
Class B common stock | AOG
Increase (Decrease) in Stockholders' Equity
Exchanges of AOG Units (in shares)	0
Class C common stock
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Number of shares sold (in shares)	115,199,620
Increase (Decrease) in Stockholders' Equity
Balance (in shares)	1
Issuance of stock (in shares)	115,199,620
Stock option exercises (in shares)	0
Vesting of restricted stock awards, net of shares withheld for tax (shares)	0
Balance (in shares)	115,199,621
Class C common stock | AOG
Increase (Decrease) in Stockholders' Equity
Exchanges of AOG Units (in shares)	0