STOCKHOLDERS' EQUITY AND SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended			36 Months Ended
	Nov. 30, 1997	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	May 31, 2014	Dec. 31, 2001
Stockholders' equity and share-based compensation
Preferred Stock, shares authorized		10,000,000	10,000,000		10,000,000
Preferred Stock, par value		$ 0.01	$ 0.01		$ 0.01
Preferred Stock, shares outstanding		0	0		0
Treasury stock, shares		1,856,000	1,856,000		1,856,000
Shares Granted			0
Intrinsic value options exercised		$ 156	$ 553	$ 732
1997 Stock Incentive Plan
Stockholders' equity and share-based compensation
Options outstanding		107,000			107,000
Term of approved stock-based compensation plan	10 years
Stock Incentive Plan 2007
Stockholders' equity and share-based compensation
Term of approved stock-based compensation plan		10 years
Shares authorized for issuance under stock incentive plan						1,700,000
Shares available for future grant		194,000			194,000
1997 Employee Stock Purchase Plan
Stockholders' equity and share-based compensation
Purchase price under employee stock purchase plan as a percentage of price as of the last day of each six month offering period		95.00%
Common stock reserved for issuance		1,138,000			1,138,000
Share purchased under employee stock purchase plan		1,067,000
Nonvested Stock Units
Stockholders' equity and share-based compensation
Granted		117,000	0
Weighted-average grant-date fair values of nonvested stock awards granted		$ 24.72		$ 22.50
Total fair values of nonvested stock awards that vested		$ 2,348	$ 2,287	$ 1,854
Unearned compensation cost		$ 6,037			$ 6,037
Unrecognized compensation costs, weighted average period of recognition		7 years 8 months 12 days
Stock Equivalent Units (SEUs)
Stockholders' equity and share-based compensation
Granted		23,000	95,000	99,000
Vesting period		4 years
Share repurchase program 2001
Stockholders' equity and share-based compensation
Number of share repurchased					0
Treasury stock, shares		1,682,000			1,682,000
Amount of aggregated share repurchased		$ 12,233			$ 12,233
Maximum | Nonvested Stock Units
Stockholders' equity and share-based compensation
Vesting period		15 years		15 years
Maximum | Share repurchase program 2001
Stockholders' equity and share-based compensation
Repurchase of common stock, authorized amount							$ 15,000
Maximum approximate dollar value of shares that may yet be purchased		$ 2,767			$ 2,767
Maximum | Share repurchase program 2014
Stockholders' equity and share-based compensation
Repurchase of common stock, authorized amount				$ 15,000