SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Basic EPS
Net income attributable to common stockholders	$ 54,876	$ 48,700	$ 165,585	$ 141,855
Net income attributable to common stockholders (in shares)	10,853,000	10,934,000	10,849,000	10,921,000
Net income attributable to common stockholders (in dollars per share)	$ 5.06	$ 4.45	$ 15.26	$ 12.99
Effect of dilutive securities
SARs and restricted stock units (in shares)	56,000	38,000	56,000	52,000
SARs and restricted stock units (in dollars per share)	$ (0.03)	$ (0.01)	$ (0.08)	$ (0.06)
Net income, diluted EPS	$ 54,876	$ 48,700	$ 165,585	$ 141,855
Weighted-average shares, diluted EPS (in shares)	10,909,000	10,972,000	10,905,000	10,973,000
Diluted EPS (in dollars per share)	$ 5.03	$ 4.44	$ 15.18	$ 12.93
Stock Appreciation Rights and Restricted Stock
Effect of dilutive securities
Antidilutive securities excluded from earnings per share (in shares)	13,237	27,160	36,843	53,955
Performance Shares
Effect of dilutive securities
Antidilutive securities excluded from earnings per share (in shares)	10,962	27,580	10,962	28,865