Basic and Diluted Per Share (Tables)

6 Months Ended

Jun. 30, 2012

Basic and Diluted Per Share Data [Abstract]

Schedule of Earnings Per Share Reconciliation [Table Text Block]

The reconciliation of basic net income per common share to diluted net income per common share is shown in the following table for the three and six-month periods ended June 30, 2012 and 2011:

	June 30, 2012						June 30, 2011
	Net Income		Shares	EPS			Net Income		Shares	EPS
Three Months
Basic net income	$	56,408	48,410,917	$	1.17		$	74,875	48,399,816	$	1.55
Effect of dilutive securities:
Restricted stock	—		16,349	—			—		11,283	—
Performance units	—		53,401	(0.01		)	—		69,261	(0.01		)
Diluted net income	$	56,408	48,480,667	$	1.16		$	74,875	48,480,360	$	1.54
Six Months
Basic net income	$	121,202	48,409,305	$	2.50		$	145,429	48,398,196	$	3.00
Effect of dilutive securities:
Restricted stock	—		16,384	—			—		10,233	—
Performance units	—		55,013	—			—		70,881	—
Diluted net income	$	121,202	48,480,702	$	2.50		$	145,429	48,479,310	$	3.00