Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net income attributable to the Company	$ 13,501	$ 12,213
Weighted average number of shares used in calculating basic net income per share	32,041	31,882
Stock options	40	90
Weighted average number of shares used in calculating diluted net income per share	32,081	31,972
Average market price of common stock used for calculation of dilutive shares	$ 35.23	$ 37.36
Basic	0.42	0.38
Diluted	$ .42	$ .38