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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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DEBT - Paragraph (Details) $ in Thousands				1 Months Ended	3 Months Ended
DEBT - Paragraph (Details) $ in Thousands	Nov. 01, 2019 USD ($)	Aug. 06, 2019	Apr. 18, 2017 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
DEBT
Notional amount				$ 500,000	$ 500,000
Interest rate swap agreement
DEBT
Notional amount				$ 500,000	500,000
Percentage of outstanding debt				58.00%
Net loss related to terminated swap				$ 1,800
Sweep Arrangements
DEBT
Advances outstanding				396	396
Credit agreement
DEBT
Maximum borrowing capacity			$ 500,000
Loan amount				$ 417,396	$ 417,396	$ 327,000
Contractual term			5 years
Accordion feature	$ 250,000		$ 200,000
Percentage of EBITDA plus certain additional amounts used to determine additional borrowing capacity	100.00%
Effective interest rate (as a percent)				3.96%	3.96%
Availability for borrowings under line of credit				$ 75,900	$ 75,900
Equity interest in domestic subsidiaries pledged as security (as a percent)			100.00%
Voting equity interest in foreign subsidiaries pledged as security (as a percent)			65.00%
Non-voting equity interest in foreign subsidiaries pledged as security (as a percent)			100.00%
Minimum consolidated senior secured leverage ratio			3.00
Total leverage ratio		4.00	4.00
Credit agreement \| Minimum
DEBT
Commitment fee (as a percent)					0.175%
Credit agreement \| Maximum
DEBT
Commitment fee (as a percent)					0.35%
Credit agreement \| Equal To Or Greater Than 3.25 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			3.25
Credit agreement \| Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			2.50
Maximum consolidated senior secured leverage ratio			3.25
Credit agreement \| Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			1.75
Maximum consolidated senior secured leverage ratio			2.50
Credit agreement \| Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			1.00
Maximum consolidated senior secured leverage ratio			1.75
Credit agreement \| Less Than 1.00 to 1.00
DEBT
Maximum consolidated senior secured leverage ratio			1.00
Credit agreement \| LIBOR \| Equal To Or Greater Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			2.00%
Credit agreement \| LIBOR \| Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			1.75%
Credit agreement \| LIBOR \| Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Percentage points added to the reference rate			1.50%
Credit agreement \| LIBOR \| Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Percentage points added to the reference rate			1.25%
Credit agreement \| LIBOR \| Less Than 1.00 to 1.00
DEBT
Percentage points added to the reference rate			1.00%
Credit agreement \| Base rate \| Equal To Or Greater Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			1.00%
Credit agreement \| Base rate \| Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			0.75%
Credit agreement \| Base rate \| Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Percentage points added to the reference rate			0.50%
Credit agreement \| Base rate \| Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Percentage points added to the reference rate			0.25%
Credit agreement \| Base rate \| Less Than 1.00 to 1.00
DEBT
Percentage points added to the reference rate			0.00%
Credit Agreement, Letter Of Credit
DEBT
Maximum borrowing capacity			$ 75,000
Line of credit issued in the form of a standby letters of credit				6,700	$ 6,700
Credit Agreement, Swingline Loans
DEBT
Maximum borrowing capacity	$ 40,000		$ 40,000
Credit Agreement, Swingline Loans \| Sweep Arrangements
DEBT
Maximum borrowing capacity				40,000	40,000
Incremental Term Loans
DEBT
Increase in capacity	50,000
Maximum borrowing capacity	$ 450,000
Loan amount				$ 400,000	$ 400,000
Contractual term	7 years
Required annual principal repayment (as a percent)	1.00%
Effective interest rate (as a percent)				4.39%	4.39%
Incremental Term Loans \| LIBOR
DEBT
Percentage points added to the reference rate	2.25%
Incremental Term Loans \| LIBOR \| Step Up Rate Based on Credit Ratings
DEBT
Percentage points added to the reference rate	2.50%
Incremental Term Loans \| Base rate
DEBT
Percentage points added to the reference rate	1.25%
Incremental Term Loans \| Base rate \| Step Up Rate Based on Credit Ratings
DEBT
Percentage points added to the reference rate	1.50%