LONG-TERM OBLIGATIONS (Details) € in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 EUR (€)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Long-Term Obligations
Revolving credit facility maximum borrowing capacity		$ 300,000	$ 300,000
Revolving credit facility maturity date			Jul. 01, 2022
Consolidated Leverage Ratio		1.17	1.17
Consolidated Interest Coverage Ratio		13.38	13.38
Long-term obligations gross including current maturities		$ 1,411,552	$ 1,411,552	$ 778,788
Current maturities of long-term obligations		(136,392)	(136,392)	(4,603)
Total long-term obligations		1,275,161	1,275,161	774,185
Deferred Finance Costs, Net, Total		3,692	3,692	1,448
Deferred debt issuance costs current		(62)	(62)
Deferred debt issuance costs noncurrent		3,631	3,631	1,448
Long-term obligations including current maturities		1,407,860	1,407,860	777,340
Current maturities of long-term obligations		(136,330)	(136,330)	(4,603)
Long-term obligations, net of unamortized debt issuance costs		1,271,530	1,271,530	772,737
Aggregate long-term maturities, excluding capital lease obligations
Sept 30,2018		136,105	136,105
Sept 30,2019		60,750	60,750
Sept 30,2020		57,909	57,909
Sept 30,2021		141,911	141,911
Sept 30,2022		132,912	132,912
Thereafter		$ 881,086	$ 881,086
Minimum
Long-Term Obligations
Consolidated Interest Coverage Ratio		3.00	3.00
Maximum
Long-Term Obligations
Consolidated Leverage Ratio		3.50	3.50
Revolving credit facility
Long-Term Obligations
Proceeds from debt | €	€ 150,000
Term of debt	5 years	5 years
Interest rate on notes (as a percent)		1.10%	1.10%
Notes payable to banks
Long-Term Obligations
Proceeds from debt		$ 280,000
Term of debt	5 years	5 years
Long-term obligations gross including current maturities		$ 280,000	$ 280,000
Deferred Finance Costs, Net, Total		755	755
Long-term obligations including current maturities		$ 279,245	$ 279,245
Interest rate on notes (as a percent)		1.36%	1.36%
Floating interest rate prior to conversion to a fixed interest rate		2.56%	2.56%
Notes payable 0.61% - 18.00%, due in monthly and annual installments through 2025
Long-Term Obligations
Long-term obligations gross including current maturities		$ 17,103	$ 17,103	18,246
Long-term obligations including current maturities		$ 17,103	$ 17,103	$ 18,246
Notes payable 0.61% - 18.00%, due in monthly and annual installments through 2025 | Minimum
Long-Term Obligations
Interest rate on notes (as a percent)		0.61%	0.61%	0.61%
Notes payable 0.61% - 18.00%, due in monthly and annual installments through 2025 | Maximum
Long-Term Obligations
Interest rate on notes (as a percent)		18.00%	18.00%	16.00%
Senior unsecured notes 6.0%, due in 2018
Long-Term Obligations
Long-term obligations gross including current maturities		$ 75,000	$ 75,000	$ 75,000
Deferred Finance Costs, Net, Total		62	62	37
Long-term obligations including current maturities		$ 74,938	$ 74,938	$ 74,963
Interest rate on notes (as a percent)		6.00%	6.00%	6.00%
Senior unsecured notes 3.8%, due in 2020
Long-Term Obligations
Long-term obligations gross including current maturities		$ 84,000	$ 84,000	$ 84,000
Deferred Finance Costs, Net, Total		138	138	119
Long-term obligations including current maturities		$ 83,862	$ 83,862	$ 83,881
Interest rate on notes (as a percent)		3.80%	3.80%	3.80%
Senior unsecured notes 3.2%, due in 2022
Long-Term Obligations
Long-term obligations gross including current maturities		$ 75,000	$ 75,000	$ 75,000
Deferred Finance Costs, Net, Total		156	156	138
Long-term obligations including current maturities		$ 74,844	$ 74,844	$ 74,862
Interest rate on notes (as a percent)		3.20%	3.20%	3.20%
Senior unsecured notes 3.5%, due in 2023
Long-Term Obligations
Long-term obligations gross including current maturities		$ 125,000	$ 125,000	$ 125,000
Deferred Finance Costs, Net, Total		291	291	256
Long-term obligations including current maturities		$ 124,709	$ 124,709	$ 124,744
Interest rate on notes (as a percent)		3.50%	3.50%	3.50%
Senior unsecured notes 0.98%, due in 2023
Long-Term Obligations
Proceeds from private placement | €	€ 100,000
Term of debt	6 years	6 years
Long-term obligations gross including current maturities		$ 118,190	$ 118,190
Deferred Finance Costs, Net, Total		418	418
Long-term obligations including current maturities		$ 117,772	$ 117,772
Interest rate on notes (as a percent)		0.98%	0.98%
Senior unsecured notes 3.4%, due in 2024
Long-Term Obligations
Long-term obligations gross including current maturities		$ 50,000	$ 50,000	$ 50,000
Deferred Finance Costs, Net, Total		118	118	104
Long-term obligations including current maturities		$ 49,882	$ 49,882	$ 49,896
Interest rate on notes (as a percent)		3.40%	3.40%	3.40%
Senior unsecured notes 3.5%, due in 2024
Long-Term Obligations
Long-term obligations gross including current maturities		$ 100,000	$ 100,000	$ 100,000
Deferred Finance Costs, Net, Total		291	291	256
Long-term obligations including current maturities		$ 99,709	$ 99,709	$ 99,744
Interest rate on notes (as a percent)		3.50%	3.50%	3.50%
Senior unsecured notes 1.17%, due in 2024
Long-Term Obligations
Proceeds from private placement | €	€ 200,000
Term of debt	7 years	7 years
Long-term obligations gross including current maturities		$ 236,380	$ 236,380
Deferred Finance Costs, Net, Total		835	835
Long-term obligations including current maturities		$ 235,545	$ 235,545
Interest rate on notes (as a percent)		1.17%	1.17%
Senior unsecured notes 3.6%, due in 2025
Long-Term Obligations
Long-term obligations gross including current maturities		$ 125,000	$ 125,000	$ 125,000
Deferred Finance Costs, Net, Total		314	314	269
Long-term obligations including current maturities		$ 124,686	$ 124,686	$ 124,731
Interest rate on notes (as a percent)		3.60%	3.60%	3.60%
Senior unsecured notes 3.6%, due in 2026
Long-Term Obligations
Long-term obligations gross including current maturities		$ 125,000	$ 125,000	$ 125,000
Deferred Finance Costs, Net, Total		314	314	269
Long-term obligations including current maturities		$ 124,686	$ 124,686	$ 124,731
Interest rate on notes (as a percent)		3.60%	3.60%	3.60%
Capital lease obligations
Long-Term Obligations
Long-term obligations gross including current maturities		$ 879	$ 879	$ 1,542
Long-term obligations including current maturities		$ 879	$ 879	$ 1,542