QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 284,161	$ 231,172	$ 431,316	$ 353,890	$ 464,693	$ 257,160	$ 181,005	$ 161,679	$ 1,300,539	$ 1,064,537	$ 1,100,120
Operating income	16,529	46,639	33,399	53,743	70,254	42,312	(8,295)	2,539	150,310	106,806	222,370
Net income	(1,001)	30,043	13,328	31,925	37,924	23,847	(5,879)	1,834	74,295	57,726	166,623
Net income attributable to common stockholders	$ (1,100)	$ 29,758	$ 13,477	$ 31,821	$ 37,261	$ 23,365	$ (5,088)	$ 1,474	$ 73,956	$ 57,012	$ 168,404
Earnings per share:
Basic earnings (loss) per share: (in dollars per share)	$ (0.03)	$ 0.69	$ 0.31	$ 0.74	$ 0.87	$ 0.54	$ (0.12)	$ 0.03	$ 1.71	$ 1.32	$ 4.07
Diluted earnings (loss) per share: (in dollars per share)	$ (0.03)	$ 0.69	$ 0.31	$ 0.74	$ 0.86	$ 0.54	$ (0.12)	$ 0.03	$ 1.71	$ 1.32	$ 3.91
Weighted-average shares outstanding:
Basic (in shares)	43,190	43,134	43,113	43,106	43,075	43,066	42,573	42,976	43,136	43,036	41,364
Diluted (in shares)	43,356	43,428	43,271	43,257	43,250	43,317	42,942	43,363	43,308	43,237	43,089