INCOME TAXES - Income tax rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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)	1.60%	1.00%	1.10%
Exempt municipal bond interest (as a percent)	(0.10%)	(0.10%)	(0.10%)
Foreign tax rates (as a percent)	0.50%	(0.40%)	(1.30%)
Qualified domestic production activities deduction (as a percent)	(0.80%)	(2.70%)	(2.60%)
Tax credits receivable (as a percent)	(1.40%)	(0.50%)	(1.20%)
Adjustment of deferred tax balances (as a percent)	(24.20%)	(0.50%)	0.20%
Reserve for uncertain tax benefits (as a percent)	(0.30%)		(2.10%)
Worthless stock deduction (as a percent)	(3.80%)
Other, net (as a percent)	(1.90%)	(0.60%)	(0.40%)
Effective income tax rate (as a percent)	4.60%	31.20%	28.60%
Dividends received deduction for certain qualified dividends foreign subsidiaries (as a percent)	100.00%
Portion of unrecognized tax benefits that, if recognized, would favorably affect annual effective income tax rate	$ 2,475	$ 2,761
Interest and penalties included in liability for uncertain tax positions	475	439
Reconciliation of the beginning and ending balances of the total amounts of unrecognized tax benefits
Unrecognized tax benefits at the beginning of the period	4,746	4,680	$ 6,993
Increases in tax positions for the current year	394	803	812
Reductions in tax positions for lapse of statute of limitations	(793)	(718)	(865)
Reductions in tax positions relating to settlements with taxing authorities		(27)	(772)
Increases in prior period unrecognized tax benefits		8
Decreases in prior period unrecognized tax benefits	(5)		(1,488)
Unrecognized tax benefits at the end of the period	4,342	$ 4,746	$ 4,680
Canada
Effective income tax rate differs from the statutory rate
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2028	3,075
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2031	665
Spain
Effective income tax rate differs from the statutory rate
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2026	301
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2027	64
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2028	192
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2029	109
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2030	331
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2031	441
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2032	332
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2033	134
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2034	464
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2035	670
Mexico
Effective income tax rate differs from the statutory rate
Tax benefits of foreign subsidiary tax loss carry forwards expiring in 2036	$ 492