Stockholders' Equity - Summary of Restricted Stock and Restricted Stock Units Activity (Details) - Restricted Stock and Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Beginning balance (in shares)	437,971	293,419	360,769
Shares granted	279,729	336,434	127,469
Vested shares	(212,984)	(152,714)	(164,144)
Shares forfeited	(43,454)	(39,168)	(30,675)
Ending balance (in shares)	461,262.000	437,971	293,419
Weighted Average Grant Price and Fair Value
Beginning balance (in dollars per share)	$ 21.54	$ 35.86	$ 37.03
Shares granted (in dollars per share)	23.35	16.34	35.15
Vested shares (in dollars per share)	25.98	35.83	37.85
Shares forfeited (in dollars per share)	21.04	25.46	36.76
Ending balance (in dollars per share)	$ 20.91	$ 21.54	$ 35.86