STOCK-BASED COMPENSATION (Details) - USD ($)		3 Months Ended						9 Months Ended
		Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		$ 2,766,000	$ 2,771,000	$ 3,477,000	$ 2,855,000	$ 3,062,000	$ 2,594,000
Award Recipient Type Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		$ 174,000			230,000			$ 591,000	$ 336,000
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares vested as of the vesting date								$ 12,208,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (minimum)								0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (maximum)								135,133
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number		84,564	84,616					84,564		102,508
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value (in shares)		$ 153.78	$ 153.76					$ 153.78		$ 133.29
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	[1],[2]	0						61,875
Grant date fair value of shares issued (in dollars per share)	[1],[2]	$ 0						$ 149.05
Forfeited (in shares)		0						(1,015)
Forfeited (per share)		$ 0						$ 144.79
Vested (in shares)		(52)						(78,804)
Vested (per share)		$ 120.39						$ 123.53
Fair value of shares granted, as of the grant dates								$ 9,222,000
Restricted stock [Member] | Award Recipient Type Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		$ 2,593,000			2,625,000			8,424,000	8,175,000
Stock-based compensation costs capitalized as development costs		$ 886,000			$ 645,000			$ 2,180,000	$ 1,981,000
Company performance based award | Executive Officer [Member] | End of one-year performance period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								34.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								1 year
Company performance based award | Executive Officer [Member] | Each of the following two years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								33.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								2 years
Individual performance based award | Executive Officer [Member] | End of one-year performance period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								34.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								1 year
Individual performance based award | Executive Officer [Member] | Each of the following two years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								33.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								2 years
Total shareholder return | Executive Officer [Member] | Following year after performance period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								25.00%
Total shareholder return | Executive Officer [Member] | End of three-year performance period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								75.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								3 years
Continuing employment awards | Executive Officer [Member] | Each year of 4-year service period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								4 years

[1] Does not include the restricted shares that may be earned if the performance goals established in 2021 and 2022 for long-term performance and in 2023 for annual and long-term performance are achieved. Depending on the actual level of achievement of the goals at the end of the open performance periods, the number of shares earned could range from zero to 135,133.

[2] Includes shares granted in prior years for which performance conditions have been satisfied and the number of shares have been determined.