LEASES - Maturities of lease liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
LEASES
2019 (excluding the nine months ended September 30, 2019)	$ 4,247
2020	13,516
2021	13,510
2022	12,551
2023	10,693
Thereafter	28,062
Total lease payments	82,579
Less imputed interest	(13,002)
Total	$ 69,577
Maturities of lease liabilities as of December 31, 2018
2019		$ 11,801
2020		12,650
2021		11,491
2022		10,713
2023		9,990
Thereafter		27,325
Total lease payments		$ 83,970

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Amount of lessee's undiscounted obligation for lease payments for operating lease.

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Amount of lessee's undiscounted obligation for lease payments for operating lease having an initial or remaining lease term in excess of one year due in remainder of fiscal year following latest fiscal year.

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