Consolidated Statements of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at Jun. 30, 2016	$ 49	$ 856,827	$ 183,018	$ (12,838)	$ 1,027,056	$ 90,379	$ 1,117,435
Balance (in shares) at Dec. 31, 2015	49,107
Balance at Dec. 31, 2015	$ 49	849,223	148,396	(7,667)	990,001	93,873	1,083,874
Stock-based compensation		1,659			1,659		1,659
Exercise of options by employees and directors (in shares)	460
Exercise of options by employees and directors		5,945			5,945		5,945
Cash paid to non controlling interest						(5,752)	(5,752)
Cash dividend declared			(18,998)		(18,998)		(18,998)
Net income			53,620		53,620	2,258	55,878
Other comprehensive income (loss), net of related taxes:
Change in foreign currency translation adjustments
Loss in respect of derivative instruments designated for cash flow hedge				43	43		43
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment				(5,166)	(5,166)		(5,166)
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge				(48)	(48)		(48)
Balance (in shares) at Jun. 30, 2016	49,567
Balance at Jun. 30, 2017	$ 50	875,591	274,566	(6,933)	1,143,274	84,325	1,227,599
Balance (in shares) at Dec. 31, 2016	49,667
Balance at Dec. 31, 2016	$ 50	869,463	216,644	(7,732)	1,078,425	91,582	1,170,007
Stock-based compensation		5,343			5,343		5,343
Exercise of options by employees and directors (in shares)	243
Exercise of options by employees and directors		785			785		785
Cash paid to non controlling interest						(14,594)	(14,594)
Cash dividend declared			(12,426)		(12,426)		(12,426)
Net income			70,348		70,348	6,941	77,977
Other comprehensive income (loss), net of related taxes:
Change in foreign currency translation adjustments				1,143	1,143	396	1,539
Loss in respect of derivative instruments designated for cash flow hedge				42	42		42
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment				(347)	(347)		(347)
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge				$ (39)	$ (39)		$ (39)
Balance (in shares) at Jun. 30, 2017	49,910