LEASES (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) location	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Leases [Abstract]
Number of buildings and offices under operating leases | location			104
Operating right-of-use lease assets	$ 58,114		$ 58,114		$ 61,766
Operating lease liabilities	$ 61,869		$ 61,869		$ 65,818
Weighted-average remaining lease term: Operating leases	5 years 10 months 24 days		5 years 10 months 24 days		6 years 2 months 12 days
Weighted-average discount rate: Operating leases	3.40%		3.40%		3.70%
Operating lease cost	$ 4,104	$ 3,818		$ 11,650
Operating Lease, Expense			$ 12,517
Short-term lease costs	28	62	78	284
Variable lease cost	619	623	2,169	1,751
Less sublease income	(235)	(228)	(716)	(696)
Total lease cost	4,516	$ 4,275		$ 12,989
Lessee, Operating Leases, Total Cost			14,048
Operating cash flows paid for operating lease amounts	4,100		3,800
Right-of-use assets in exchange for operating lease liabilities	4,100		8,800
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	4,147		4,147
2020	15,739		15,739
2021	12,830		12,830
2022	9,813		9,813
2023	7,848		7,848
Thereafter	18,012		18,012
Total minimum lease payments	68,389		68,389
Less: amount of lease payments representing interest	(6,520)		(6,520)
Operating lease liabilities	$ 61,869		61,869		$ 65,818
Undiscounted lease payments under an operating lease that had not yet commenced			$ 0