Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net income attributable to the Company													$ 41,569	$ 17,517	$ 30,977
Weighted average number of shares used in calculating basic net income/(loss) per share													31,832,000	31,649,000	31,356,000
Stock options													99,000	129,000	57,000
Long-term incentive plan													57,000	156,000	223,000
Weighted average number of shares used in calculating diluted net income per share													31,988,000	31,934,000	31,636,000
Average market price of common stock used for calculation of dilutive shares													$ 36.29	$ 31.85	$ 21.51
Basic	$ 0.26	$ 0.37	$ 0.35	$ 0.33	$ 0.27	$ 0.15	$ (0.23)	$ 0.36	$ 0.27	$ 0.30	$ (1.08)	$ 1.50	$ 1.31	$ 0.55	$ 0.99
Diluted	$ 0.25	$ 0.37	$ 0.35	$ 0.33	$ 0.27	$ 0.15	$ (0.23)	$ 0.36	$ 0.26	$ 0.30	$ (1.08)	$ 1.49	$ 1.30	$ 0.55	$ 0.97	[1]
Common Stock, shares outstanding	31,900,000				31,800,000				31,400,000				31,900,000	31,800,000	31,400,000

[1] Due to a loss from continuing operations in 2012, the calculation of diluted income per share cannot be calculated by dividing net income by the diluted shares in the table above. See Statement of Income.