Equity-Based Compensation - Summary of Stock Option Activity Under the 2010 Plan and Equity Plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
2010 Equity Award Plan [Member]
Stock Option Activity, Options
Beginning of period, outstanding (in shares)	1,000,855	820,471	631,846
Options granted (in shares)	48,500	180,384	282,500
Stock Option Plan share issuance, shares	0	0	0
Options canceled or forfeited (in shares)	(17,350)	0	(13,500)
Options expired (in shares)	(144,950)	0	(80,375)
End of period, outstanding (in shares)	887,055	1,000,855	820,471
Options exercisable (in shares)	552,254
Weighted-Average Exercise Price
Beginning of period (weighted-average price)	$ 11.72	$ 13.21	$ 15.89
Options granted (weighted-average price)	5.38	4.95	7.51
Options exercised (weighted-average price)	0	0	0
Options canceled or forfeited (weighted-average price)	9.73	0	17.87
Options expired (weighted-average price)	9.73	0	13.49
End of period (weighted-average price)	11.74	$ 11.72	$ 13.21
Options exercisable (weighted-average price)	$ 14.87
2000 Equity Award Plan [Member]
Stock Option Activity, Options
Beginning of period, outstanding (in shares)	1,170,925	1,356,375	1,868,597
Options granted (in shares)	0	0	0
Stock Option Plan share issuance, shares	(232,750)	(182,500)	(473,472)
Options canceled or forfeited (in shares)	0	0	0
Options expired (in shares)	(203,750)	(2,950)	(38,750)
End of period, outstanding (in shares)	734,425	1,170,925	1,356,375
Options exercisable (in shares)	734,425
Weighted-Average Exercise Price
Beginning of period (weighted-average price)	$ 4.98	$ 4.89	$ 4.82
Options granted (weighted-average price)	0	0	0
Options exercised (weighted-average price)	4.09	4.27	4.66
Options canceled or forfeited (weighted-average price)	0	0	0
Options expired (weighted-average price)	5.48	5.79	4.13
End of period (weighted-average price)	5.13	$ 4.98	$ 4.89
Options exercisable (weighted-average price)	$ 5.13