Stock Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Employee Restricted Common Stock Grant Awards

The following table summarizes employee restricted common stock grant awards by year for grant years with unvested shares outstanding at December 31, 2016 and the remaining vesting schedule.

	2016	2015	2014
Number of shares of restricted common stock:
Granted during the year	663,960	401,520	482,001
Unvested at December 31, 2016	425,160	118,220	28,387
Scheduled to vest during the year ending:
December 31, 2017	212,580	118,220	28,387
December 31, 2018	212,580	—	—

Summary of Restricted Stock Units

The following table summarizes restricted stock units awarded by year for grant years with unvested units outstanding at December 31, 2016.

	2016		2015		2014
Number of shares of restricted stock units:
Granted during the year		—		409,800		395,900
Unvested at December 31, 2016		—		377,800		327,800
Vest date	N/A		February 1, 2018		February 1, 2017
Performance measurement period:
Fiscal year ended	N/A		December 31, 2017		December 31, 2016

Summary of Restricted Common Stock and Performance-Based Restricted Stock Unit Activity

The following table summarizes restricted common stock and performance-based restricted stock unit activity in our stock incentive plans for the year ended December 31, 2016.

	Restricted Common Stock						Restricted Stock Units
	Number of Shares		Weighted Average Grant Date Fair Value				Number of Units		Weighted Average Grant Date Fair Value
Unvested at beginning of year	374,817			$	12.68		751,500			$	12.41
Granted	685,872			15.06			—			—
Vested	(323,010	)		(14.04		)	—			—
Forfeited	(33,350	)		(14.43		)	(45,900	)		(12.39		)
Expired	(65,000	)	(1)	(13.23		)	—			—
Unvested at end of year	639,329			14.40			705,600			12.41

(1) Expired on June 30, 2016. Performance-based conditions were not achieved.

Summary of Option Activity

The following table summarizes option activity in our stock incentive plans for the year ended December 31, 2016.

	Number of Options			Weighted Average Exercise Price
Outstanding at beginning of year		12,000			$	29.76
Expired		(6,000	)		(29.79		)
Outstanding and exercisable at end of year		6,000			29.72