Debt - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			1 Months Ended		1 Months Ended	9 Months Ended							9 Months Ended			1 Months Ended	9 Months Ended			1 Months Ended				1 Months Ended		9 Months Ended		9 Months Ended						9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Nov. 30, 2012 Loan Agreement	Sep. 30, 2014 Loan Agreement	Apr. 30, 2012 Unsecured Debt Convertible Senior Notes	Sep. 30, 2014 Unsecured Debt Convertible Senior Notes	Sep. 30, 2014 Unsecured Debt Convertible Senior Notes Scenario 1	Sep. 30, 2014 Unsecured Debt Convertible Senior Notes Scenario 2	Sep. 30, 2014 Amended Credit Agreement	Sep. 30, 2013 Amended Credit Agreement	Sep. 30, 2014 Amended Credit Agreement Loan Agreement	Sep. 30, 2014 Revolving Credit Facility	Sep. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement	Sep. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement Option to increase subject to certain conditions	Sep. 30, 2014 Revolving Credit Facility Amended and Restated Credit Agreement Swing Line Loan	Apr. 30, 2013 Term Loan Credit Facilty	Sep. 30, 2014 Term Loan Credit Facilty	Dec. 31, 2013 Term Loan Credit Facilty	Apr. 30, 2013 Term Loan Credit Facilty Convertible Senior Notes	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	Sep. 30, 2014 Letter Of Credit Subfacility Revolving Credit Facility Amended and Restated Credit Agreement	Sep. 30, 2014 Minimum Unsecured Debt Convertible Senior Notes Scenario 1	Sep. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement	Sep. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement LIBOR	Sep. 30, 2014 Minimum Revolving Credit Facility Amended and Restated Credit Agreement Base Rate	Sep. 30, 2014 Minimum Term Loan Credit Facilty Through September 30, 2013	Sep. 30, 2014 Minimum Term Loan Credit Facilty Thereafter through September 30, 2015	Sep. 30, 2014 Minimum Term Loan Credit Facilty Thereafter	Sep. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement	Sep. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement LIBOR	Sep. 30, 2014 Maximum Revolving Credit Facility Amended and Restated Credit Agreement Base Rate	Sep. 30, 2014 Maximum Term Loan Credit Facilty Through September 30, 2013	Sep. 30, 2014 Maximum Term Loan Credit Facilty Thereafter through September 30, 2015	Sep. 30, 2014 Maximum Term Loan Credit Facilty Thereafter
Debt Instrument [Line Items]
Notes issued, aggregate principal amount	$ 344,610,000		$ 344,610,000		$ 387,042,000	$ 2,500,000		$ 150,000,000	$ 150,000,000					$ 42,100,000						$ 192,845,000	$ 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																														1.0						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															219,700,000												297,000,000
Interest Paid												7,900,000	12,000,000
Long-term debt	323,689,000		323,689,000		358,890,000		1,800,000																				277,000,000
Senior leverage ratio																																	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	490,000		490,000		3,245,000		500,000
Debt issuance costs paid			0	981,000								8,500,000
Interest expense	5,454,000	6,252,000	16,904,000	20,364,000								700,000	700,000
Line of credit facility, decrease, repayments			565,000	910,000																							20,000,000
Percentage of tranche loan amount on equal quarterly installments																			0.25%
Debt Conversion, Converted Instrument, Amount									21,000,000
Line of Credit Facility, Amount Outstanding																25,000,000									300,000,000
Other Expenses												$ 900,000	$ 900,000