ACCOUNTING POLICIES - Adopted Pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Accounting Pronouncements
Retained earnings	$ 595,932		$ 533,187
ASC Topic 326, Financial Instruments-Credit Losses
Assets and liabilities
Change in Accounting Principle, Accounting Standards Update, Adopted		true
ASC Topic 326, Financial Instruments-Credit Losses | Cumulative Effect, Period of Adoption, Adjustment
Accounting Pronouncements
Retained earnings			$ (200)
ASC Topic 350-40, Goodwill and Other-Internal-Use Software
Assets and liabilities
Change in Accounting Principle, Accounting Standards Update, Adopted		true
ASC Topic 820, Fair Value Measurement
Assets and liabilities
Change in Accounting Principle, Accounting Standards Update, Adopted		true