STOCKHOLDERS' EQUITY - Dividend Activity (Details) - USD ($) $ / shares in Units, $ in Thousands									12 Months Ended
Nov. 23, 2018	Aug. 24, 2018	May 25, 2018	Mar. 09, 2018	Nov. 24, 2017	Aug. 31, 2017	May 19, 2017	Mar. 03, 2017	Dec. 31, 2018	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Special dividend per common share (in dollars per share)	$ 0.18	$ 0.25	$ 1.76		$ 0.15	$ 0.25	$ 0.35	$ 0.35
Special dividend amount	$ 2,048	$ 2,844	$ 20,022		$ 1,701	$ 2,833	$ 3,964	$ 3,962
Dividend per common share (in dollars per share)	$ 0.16	$ 0.15	$ 0.14	$ 0.13	$ 0.12	$ 0.11	$ 0.10	$ 0.09	$ 2.77	$ 1.52
Dividend amount	$ 1,820	$ 1,707	$ 1,592	$ 1,479	$ 1,360	$ 1,246	$ 1,133	$ 1,019	$ 31,512	$ 17,218
Payment Date	Nov. 23, 2018	Aug. 24, 2018	May 25, 2018	Mar. 09, 2018	Nov. 24, 2017	Aug. 31, 2017	May 19, 2017	Mar. 03, 2017

Common Stock, Special Dividends, Per Share, Cash Paid

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Special Dividends, Common Stock, Cash

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Aggregate dividends paid during the period for each share of common stock outstanding.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Date the declared dividend will be paid, in CCYY-MM-DD format.

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-Name Accounting Standards Codification
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Amount of paid and unpaid cash dividends declared for classes of stock, for example, but not limited to, common and preferred.

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