Condensed Consolidated Statements of Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2012	$ 46	$ 732,140	$ (44,326)	$ 651	$ 688,511	$ 7,096	$ 695,607
Balance (in Shares) at Dec. 31, 2012	45,431
Stock-based compensation		4,548			4,548		4,548
Exercise of options by employees and directors		437			437		437
Exercise of options by employees and directors (in Shares)	23
Cash paid to noncontrolling interest						(509)	(509)
Cash dividend declared, per share			(1,816)		(1,816)		(1,816)
Increase in noncontrolling interest						5,151	5,151
Net income			33,076		33,076	600	33,676
Other comprehensive loss, net of related taxes:
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge (net of related tax)				(124)	(124)		(124)
Balance at Sep. 30, 2013	46	737,125	(13,066)	527	724,632	12,338	736,970
Balance (in Shares) at Sep. 30, 2013	45,454
Balance at Dec. 31, 2013	46	735,295	(3,088)	487	732,740	12,371	745,111
Balance (in Shares) at Dec. 31, 2013	45,461
Stock-based compensation		4,308			4,308		4,308
Exercise of options by employees and directors		889			889		889
Exercise of options by employees and directors (in Shares)	70
Cash paid to noncontrolling interest						(589)	(589)
Cash dividend declared, per share			(7,279)		(7,279)		(7,279)
Acquisition of noncontrolling interest in Crump		159			159	(987)	(828)
Increase in noncontrolling interest						257	257
Net income			47,202		47,202	670	47,872
Other comprehensive loss, net of related taxes:
Loss in respect of derivative instruments designated for cash flow hedge (net of related tax of $572)				(933)	(933)		(933)
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment (net of related tax of $0)				(5,157)	(5,157)		(5,157)
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge (net of related tax)				(107)	(107)		(107)
Balance at Sep. 30, 2014	$ 46	$ 740,651	$ 36,835	$ (5,710)	$ 771,822	$ 11,722	$ 783,544
Balance (in Shares) at Sep. 30, 2014	45,531