Debt - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended			6 Months Ended	1 Months Ended	6 Months Ended									6 Months Ended			1 Months Ended	12 Months Ended			1 Months Ended				1 Months Ended		6 Months Ended								6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Nov. 30, 2012 Loan Agreement	Jun. 30, 2014 Loan Agreement	Apr. 30, 2013 Convertible Senior Notes	Jun. 30, 2014 Amended and Restated Credit Agreement	Apr. 30, 2012 Unsecured Debt Convertible Senior Notes	Jun. 30, 2014 Unsecured Debt Convertible Senior Notes	Jun. 30, 2014 Unsecured Debt Convertible Senior Notes Scenario 1	Jun. 30, 2014 Unsecured Debt Convertible Senior Notes Scenario 2	Jun. 30, 2014 Amended Credit Agreement	Jun. 30, 2013 Amended Credit Agreement	Apr. 30, 2013 Amended Credit Agreement	Jun. 30, 2014 Amended Credit Agreement Loan Agreement	Jun. 30, 2013 Amended Credit Agreement Loan Agreement	Jun. 30, 2014 Revolving Credit Facility	Jun. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement	Jun. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement Option to increase subject to certain conditions	Jun. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement Swing Line Loan	Apr. 30, 2013 Term Loan Credit Facilty	Dec. 31, 2012 Term Loan Credit Facilty	Jun. 30, 2014 Term Loan Credit Facilty	Dec. 31, 2013 Term Loan Credit Facilty	Apr. 30, 2013 Term Loan Credit Facilty LIBOR	Apr. 30, 2013 Term Loan Credit Facilty Base Rate	May 31, 2012 Term Loan Credit Facilty Senior Secured Credit Facility	May 31, 2012 Term Loan Credit Facilty Incremental Senior Credit Facility	Apr. 30, 2013 Term Loan Credit Facilty Amended Credit Agreement	Jun. 30, 2014 Letter Of Credit Subfacility Revolving Credit Facility Amended and Restated Credit Agreement	Jun. 30, 2014 Minimum Unsecured Debt Convertible Senior Notes Scenario 1	Jun. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement	Jun. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement LIBOR	Jun. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement Base Rate	Jun. 30, 2014 Minimum Term Loan Credit Facilty Through September 30, 2013	Jun. 30, 2014 Minimum Term Loan Credit Facilty Thereafter through September 30, 2015	Jun. 30, 2014 Minimum Term Loan Credit Facilty Thereafter	Jun. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement	Jun. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement LIBOR	Jun. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement Base Rate	Jun. 30, 2014 Maximum Term Loan Credit Facilty Through September 30, 2013	Jun. 30, 2014 Maximum Term Loan Credit Facilty Thereafter through September 30, 2015	Jun. 30, 2014 Maximum Term Loan Credit Facilty Thereafter
Debt Instrument [Line Items]
Notes issued, aggregate principal amount	$ 365,422,000		$ 365,422,000		$ 387,042,000	$ 2,500,000				$ 150,000,000	$ 150,000,000						$ 21,400,000	$ 20,800,000							$ 213,538,000	$ 234,923,000
Notes issued, interest rate						4.25%		3.375%		3.375%
Notes issued, interest payment frequency										semi-annually
Notes initial conversion rate per 1,000 in principal amount											85.4372
Principal amount of notes conversation for 85.4372 shares of common stock											1,000
Notes initial conversion price											$ 11.70
Convertible notes, conversation date											Nov. 01, 2017
Number of trading days																																	20 days
Number of consecutive trading days												30 days	5 days
Last reported sale price of common stock as percentage of conversion price																																	130.00%
Convertible senior notes, trading price per $1,000 principal amount of notes as percentage of the product of the last reported sale price of common stock and the conversion rate													98.00%
Proceeds from notes issued											145,100,000
Estimated implied interest rate											7.00%
Fair value of liability component upon issuance											123,800,000
Difference between cash proceeds before offering expenses and the estimated fair value of liability component											21,700,000
Proceeds from issuance of convertible senior notes											145,500,000
Credit facility, maturity date						Mar. 31, 2018														May 08, 2017			May 08, 2019
Credit facility, borrowing capacity																				150,000,000	200,000,000	10,000,000								75,000,000		15,000,000
Credit facility, interest rate above basis																											3.50%	2.50%							1.75%	0.75%					2.25%	1.25%
Credit facility, unused line fee monthly payment																				0.375%
Required minimum fixed charge coverage ratio when availability under the Revolver is less than 12.5% of the total revolving commitment																																								1.1
Excess availability as a percentage of total revolving commitment below which minimum fixed charge coverage ratio maintained																				12.50%
Availability percentage threshold of total revolving commitment below which amounts in deposit accounts will be transferred daily in to blocked account																				15.00%
Line of Credit Facility, Remaining Borrowing Capacity																			222,300,000												297,000,000
Interest Paid														5,400,000	8,500,000
Long-term debt	340,104,000		340,104,000		358,890,000		1,900,000									277,000,000
Interest coverage ratio																									1.00%
Senior leverage ratio																																		1.0			1.0	1.0	1.0				4.5	4.0	3.5
Line of credit facility potential term extension period																							91 days
Debt amortization percentage																							1.00%
Proceeds from Sale of Productive Assets																								1,000,000
Current portion of long-term debt	3,255,000		3,255,000		3,245,000		500,000							2,800,000
Debt issuance costs paid			0	981,000										8,500,000
Interest expense	5,733,000	6,577,000	11,450,000	14,112,000										500,000	400,000
Line of credit facility, decrease, repayments			366,000	651,000																											20,000,000
Percentage of tranche loan amount on equal quarterly installments																							0.25%
Senior secured leverage ratio									1.2:1.0
Debt Conversion, Converted Instrument, Amount											33,000,000
Line of Credit Facility, Amount Outstanding																				25,000,000									300,000,000
Accelerated amortization			$ 2,409,000	$ 2,268,000										$ 400,000	$ 400,000