INCOME TAXES - Income tax rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective income tax rate differs from the statutory rate
U.S. statutory rate (as a percent)	35.00%	35.00%	35.00%
State income taxes, net (as a percent)	1.00%	1.10%	1.00%
Exempt municipal bond interest (as a percent)	(0.10%)	(0.10%)	(0.50%)
Foreign tax rates (as a percent)	(0.40%)	(1.30%)	(1.50%)
Qualified domestic production activities deduction (as a percent)	(2.70%)	(2.60%)	(2.80%)
Tax credits receivable (as a percent)	(0.50%)	(1.20%)	(0.60%)
Adjustment of deferred tax balances (as a percent)	(0.50%)	0.20%	1.90%
Reserve for uncertain tax benefits (as a percent)		(2.10%)
Other, net (as a percent)	(0.60%)	(0.40%)	(1.40%)
Effective income tax rate (as a percent)	31.20%	28.60%	31.10%
Foreign subsidiaries' undistributed earnings	$ 22,081	$ 20,174
Estimated federal income tax liability on foreign subsidiaries' undistributed earnings (as a percent)	30.00%
Cash and short term investments held by foreign subsidiary	$ 12,354	15,265
Portion of unrecognized tax benefits that, if recognized, would favorably affect annual effective income tax rate	2,761	2,737
Interest and penalties included in liability for uncertain tax positions	439	421
Reconciliation of the beginning and ending balances of the total amounts of unrecognized tax benefits
Unrecognized tax benefits at the beginning of the period	4,680	6,993	$ 6,010
Increases in tax positions for the current year	803	812	1,827
Increases in tax positions for new uncertain tax position			609
Reductions in tax positions for lapse of statute of limitations	(718)	(865)	(1,050)
Reductions in tax positions relating to settlements with taxing authorities	(27)	(772)	(403)
Increases in prior period unrecognized tax benefits	8
Decreases in prior period unrecognized tax benefits		(1,488)
Unrecognized tax benefits at the end of the period	4,746	$ 4,680	$ 6,993
Canada
Effective income tax rate differs from the statutory rate
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2028	2,181
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2029	3,546
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2031	619
Spain
Effective income tax rate differs from the statutory rate
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2026	264
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2027	56
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2028	168
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2029	96
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2030	290
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2031	387
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2032	291
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2033	117
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2034	$ 437