SHAREHOLDERS' EQUITY (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	May 31, 2017	Feb. 25, 2016	Jan. 14, 2016	May 07, 2014	Jan. 11, 2010
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Annual interest rate on convertible senior notes					0.625%
Calculation of weighted average common shares
Weighted average common shares, basic	11,999,000	11,754,000	11,931,000	11,827,000
Effect of dilutive securities
Effect of stock options (in shares)	1,619,000	913,000	1,598,000	877,000
Effect of dilutive share awards (in shares)	101,000	75,000	96,000	78,000
Effect of Convertible Senior Notes (in shares)	55,000	0	0	0
Weighted average common shares, diluted	13,774,000	12,742,000	13,625,000	12,782,000
Common stock repurchases
Value of common stock authorized to be repurchased						$ 40,000,000	$ 50,000,000	$ 10,000,000	$ 10,000,000
Purchase of treasury stock (in shares)	42,153		42,153	690,218
Remaining authorized repurchase amount	$ 38,700,000		$ 38,700,000
Employee stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted earnings per share (in shares)	300,000		100,000
Restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted earnings per share (in shares)	100,000