CAPITAL STOCK (Narrative) (Details) - USD ($)			3 Months Ended						9 Months Ended
	Nov. 02, 2017	Oct. 25, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	May 03, 2016
Exercise of stock options									$ 4,144,000	$ 1,839,000
Employee tax withholdings related to the vesting of equity awards									1,596,000	$ 2,652,000
Dividend paid per share to all stockholders of record (in Dollars per Share)			$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175
Purchase and retirement of common stock, value									$ 2,285,000
Preferred stock, shares authorized (in Shares)			5,000,000						5,000,000		5,000,000
Dividend Declared [Member] | Subsequent Event [Member]
Dividends payable (in Description)	Quarterly
Dividends payable, amount per share (in Dollars per Share)	$ 0.175
Dividends payable, date to be paid (Date)	Nov. 16, 2017
Dividends payable, date of record (Date)	Nov. 06, 2017
Common Stock [Member]
Exercise of stock options (in Shares)									261,000
Common stock surrendered by employees in satisfaction of minimum tax withholding associated with equity award vesting (in Shares)									34,000	128,000
Employee tax withholdings related to the vesting of equity awards									$ 1,596,000	$ 2,652,000
Common stock issued for services (in Shares)									14,000	27,000
Common stock issued for services, costs recognized									$ 700,000	$ 700,000
Purchase and retirement of common stock, shares									51,000
Purchase and retirement of common stock, value									$ 0
Share repurchase program commencement date		Nov. 04, 2017
Common Stock [Member] | Maximum [Member]
Common stock authorized to repurchase amount		$ 50,000,000										$ 50,000,000
Common Stock [Member] | Surrender of Shares by Employee [Member]
Purchase and retirement of common stock, shares									22,000
Purchase and retirement of common stock, value									$ 785,000
Common Stock [Member] | Open-market Transactions [Member]
Purchase and retirement of common stock, shares									29,000
Purchase and retirement of common stock, value									$ 1,500,000
Stock Option [Member]
Exercise of stock options (in Shares)									261,000
Stock Option [Member] | Common Stock [Member]
Exercise of stock options (in Shares)									261,000	181,000