SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Basic EPS
Net income attributable to common stockholders	$ 43,985	$ 46,955
Net income attributable to common stockholders (in shares)	10,896,000	10,847,000
Net income attributable to common stockholders (in dollars per share)	$ 4.04	$ 4.33
Effect of dilutive securities
SARs and restricted stock units (in shares)	87,000	122,000
SARs and restricted stock units (in dollars per share)	$ (0.03)	$ (0.05)
Net income, diluted EPS	$ 43,985	$ 46,955
Weighted-average shares, diluted EPS (in shares)	10,983,000	10,969,000
Diluted EPS (in dollars per share)	$ 4.01	$ 4.28
Stock Appreciation Rights and Restricted Stock
Effect of dilutive securities
Antidilutive securities excluded from earnings per share (in shares)	58,539	49,371
Performance Shares
Effect of dilutive securities
Antidilutive securities excluded from earnings per share (in shares)	29,507	29,918