Stockholders' Equity and Equity Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2012

Stockholders' Equity and Equity Compensation Plans [Abstract]

Summary of unvested restricted common stock activity

	Quarter Ended June 30, 2012					Six Months Ended June 30, 2012
	Shares			Weighted- Average Grant Date Fair Value		Shares			Weighted- Average Grant Date Fair Value
Unvested awards, beginning		2,037,763		$	17.51		1,620,394		$	17.87
Awards granted		11,000			16.20		996,691			16.39
Awards forfeited/cancelled		(31,175	)		17.69		(64,175	)		17.73
Awards vested		(5,125	)		16.28		(540,447	)		16.49
Unvested awards, ending		2,012,463		$	17.50		2,012,463		$	17.50