CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Loss (Income)	Retained Earnings (Deficit)	Noncontrolling Interests
Balance, Stockholders Equity at Dec. 31, 2014	$ 397,762	$ 35	$ 481,762	$ (19,860)	$ 15	$ (64,785)	$ 595
Balance (in shares) at Dec. 31, 2014		34,569,526
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock - employee stock purchase plan	2,204		2,204
Issuance of stock - employee stock purchase plan (shares)		79,323
Issuance of stock - 401 (k) plan	6,032		6,032
Issuance of stock - 401 (k) plan (shares)		184,412
Issuance/(cancellation) of non-vested stock	0
Issuance/(cancellation) of non-vested stock (shares)		(61,675)
Exercise of stock options	399		399
Exercise of stock options (in shares)		15,380
Non-cash compensation	11,824		11,824
Tax benefit from stock options exercised and restricted stock vesting	2,073		2,073
Tax deficit from stock options exercised and restricted stock vesting	(4)		(4)
Surrendered shares	(2,525)			(2,525)
Shares repurchased	(4,581)			(4,581)
Noncontrolling interest distribution	(436)						(436)
Net income (loss)	(2,312)					(3,021)	709
Balance, Stockholders Equity at Dec. 31, 2015	410,436	$ 35	504,290	(26,966)	15	(67,806)	868
Balance (in shares) at Dec. 31, 2015		34,786,966
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock - employee stock purchase plan	2,483		2,483
Issuance of stock - employee stock purchase plan (shares)		63,688
Issuance of stock - 401 (k) plan	6,682		6,682
Issuance of stock - 401 (k) plan (shares)		145,660
Issuance/(cancellation) of non-vested stock	0
Issuance/(cancellation) of non-vested stock (shares)		257,263
Non-cash compensation	16,401		16,401
Tax benefit from stock options exercised and restricted stock vesting	7,241		7,241
Surrendered shares	(7,493)			(7,493)
Shares repurchased	(12,315)			(12,315)
Noncontrolling interest distribution	(329)						(329)
Assets contributed to equity investment	405		375				30
Net income (loss)	37,631					37,261	370
Balance, Stockholders Equity at Dec. 31, 2016	461,142	$ 35	537,472	(46,774)	15	(30,545)	939
Balance (in shares) at Dec. 31, 2016		35,253,577
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock - employee stock purchase plan	2,382		2,382
Issuance of stock - employee stock purchase plan (shares)		53,848
Issuance of stock - 401 (k) plan	8,223		8,223
Issuance of stock - 401 (k) plan (shares)		156,487
Issuance/(cancellation) of non-vested stock	0
Issuance/(cancellation) of non-vested stock (shares)		139,016
Exercise of stock options	$ 4,554		4,554
Exercise of stock options (in shares)	144,206	144,206
Non-cash compensation	$ 16,295		16,295
Tax benefit from stock options exercised and restricted stock vesting	448					448
Surrendered shares	(6,939)			(6,939)
Noncontrolling interest distribution	(216)						(216)
Assets contributed to equity investment	(146)		(146)
Net income (loss)	30,683					30,301	382
Balance, Stockholders Equity at Dec. 31, 2017	$ 516,426	$ 35	$ 568,780	$ (53,713)	$ 15	$ 204	$ 1,105
Balance (in shares) at Dec. 31, 2017		35,747,134