Earnings Per Share Earnings per share table (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator - basic and diluted:
Net income	$ 29,539	$ 62,348	$ 30,284	$ 104,621
Allocation to participating securities	73	212	75	355
Net income applicable to common shares	$ 29,466	$ 62,136	$ 30,209	$ 104,266
Denominator - basic:	57,744	57,475	57,678	57,419
Effect of dilutive securities	602	444	607	457
Denominator - diluted:	58,346	57,919	58,285	57,876
Earnings per common share - basic:
Net income applicable to common shares - basic	$ 0.51	$ 1.08	$ 0.52	$ 1.82
Earnings per common share - diluted:
Net income applicable to common shares - diluted	$ 0.51	$ 1.07	$ 0.52	$ 1.80
Income from continuing operations [Member]
Numerator - basic and diluted:
Allocation to participating securities	$ 73	$ 212