INCOME TAXES (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Property and equipment	$ 10,561	$ 8,164
Intangible assets	2,220	827
Accrued expenses	90,754	50,639
Net operating loss carryforward	4,988	6,089
Deferred revenue	4,551	9,796
Stock-based compensation	31,959	30,112
Operating lease liabilities	52,806	51,519
Foreign tax credit	7,589	2,168
Foreign currency exchange	11,750	4,890
Other assets	2,235	1,252
Deferred tax assets	219,413	165,456
Less: valuation allowance	(4,538)	(5,485)
Total deferred tax assets	214,875	159,971
Deferred tax liabilities:
Property and equipment	1,095	3,818
Intangible assets	26,124	12,018
Operating lease right-of-use assets	51,871	50,149
Accrued revenue and expenses	2,953	991
U.S. taxation of foreign subsidiaries	3,770	1,608
Foreign currency exchange	239	1,153
Other liabilities	3,210	1,095
Total deferred tax liabilities	89,262	70,832
Net deferred tax assets	125,613	89,139
Other noncurrent liabilities
Deferred tax liabilities:
Deferred income tax liabilities, net	18,300	3,300
Business acquisitions
Deferred tax assets:
Stock-based compensation	$ 5,400	$ 6,100
Business acquisitions | Minimum
Deferred tax liabilities:
Amortization period of stock-based compensation for tax	10 years
Business acquisitions | Maximum
Deferred tax liabilities:
Amortization period of stock-based compensation for tax	15 years