Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2011

Stock-Based Compensation [Abstract]

Employee Stock-Based Compensation Costs Table

	For the three months ended		For the nine months ended
	September 30,		September 30,
	2011	2010	2011	2010
	(in thousands)
Stock-based compensation cost – general and administrative expense	$            1,933	$2,179	$6,619	$6,612
Stock-based compensation cost – capitalized	$            2,188	$1,699	$6,003	$5,096

Summary of Stock Option Activity, Options Outstanding

		Weighted
		Average
	Number	Exercise
	of Options	Price
Outstanding at December 31, 2010	4,769,122	$16.13
Granted	21,695	41.31
Exercised	(563,356)	8.60
Forfeited or expired	(25,538)	34.84
Outstanding at September 30, 2011	4,201,923	$17.16
Exercisable at September 30, 2011	3,416,457	$12.61

Summary of Restricted Stock Activity and Unvested Shares

		Weighted
		Average
	Number	Grant Date
	of Shares	Fair Value
Unvested shares at December 31, 2010	834,058	$36.24
Granted	4,965	38.35
Vested	(39,260)	38.10
Forfeited	(40,496)	36.47
Unvested shares at September 30, 2011	759,267	$36.15