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Long-Term Debt and Capital Leases - Additional Information (Detail) (USD $)	12 Months Ended		1 Months Ended	8 Months Ended	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Feb. 28, 2015	Dec. 31, 2014	Oct. 31, 2014	Apr. 30, 2014	Dec. 31, 2012
Debt Instrument [Line Items]
Net proceeds from the offering sale	$ 42,184,000
Aggregate principal amount	496,205,000us-gaap_DebtAndCapitalLeaseObligations			535,711,000us-gaap_DebtAndCapitalLeaseObligations		508,019,000us-gaap_DebtAndCapitalLeaseObligations
Loss on debt extinguishment	15,584,000	300,000
Write off Deferred Financing Costs [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment	2,767,000
Write off Unamortized Original Issue Discount [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment	2,074,000
Tender Premium and Tender Fees [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment	10,743,000
Class A Common Stock [Member]
Debt Instrument [Line Items]
Net proceeds from the offering sale	42,184,000
Abl Facility [Member] \| Senior Subordinated Notes Due 2019 Notes [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Issuance of additional senior subordinated notes			60,000,000
Maturity date			Feb. 15, 2019
Abl Facility [Member] \| Senior Secured Revolving Credit Facility Due Two Thousand Sixteen [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Maturity date			Mar. 18, 2016
Maine Bonds [Member]
Debt Instrument [Line Items]
Maturity date				Jan. 01, 2025
Debt instrument, face amount		25,000,000
Debt instrument interest rate				6.25%
Aggregate principal amount		21,400,000		21,400,000			21,400,000
Maine Bonds [Member] \| Variable Rate Bonds [Member]
Debt Instrument [Line Items]
Carrying value of bonds				3,600,000
Fixed Rate Bonds [Member]
Debt Instrument [Line Items]
Maturity date				Apr. 01, 2036
Carrying value of bonds	16,000,000			16,000,000
Debt instrument interest rate				4.75%
Revolver [Member]
Debt Instrument [Line Items]
Carrying value of bonds				131,300,000
Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Maturity date		Feb. 15, 2019		Feb. 15, 2019
Debt instrument, face amount	125,000,000	200,000,000
Additional increase in credit facility	50,000,000
Issued discount	1,863,000			476,000
Carrying value of bonds				325,000,000
Debt instrument interest rate				7.75%
Senior Subordinated Notes Due 2013 [Member]
Debt Instrument [Line Items]
Maturity date		Feb. 01, 2013
New Hampshire Bonds [Member]
Debt Instrument [Line Items]
Maturity date				Apr. 01, 2029
Carrying value of bonds				11,000,000	11,000,000
Debt instrument interest rate				4.00%
Aggregate principal amount					5,500,000
Additional bond issued					5,500,000
Second Lien Notes [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment	15,584,000
Senior Secured Revolving Credit Facility Due Two Thousand Twenty [Member] \| Abl Facility [Member]
Debt Instrument [Line Items]
Maturity date				Feb. 26, 2020
Revolving credit facility				190,000,000
Additional increase in credit facility				100,000,000
Line of credit facility interest rate description				London Interbank Offered Rate (“LIBOR”) plus between 1.75% and 2.50%
Debt instrument stated percentage				2.25%
Senior Secured Revolving Credit Facility Due Two Thousand Twenty [Member] \| Abl Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument stated percentage				1.75%
Senior Secured Revolving Credit Facility Due Two Thousand Twenty [Member] \| Abl Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt instrument stated percentage				2.50%
Senior Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date				Mar. 18, 2016
Revolving credit facility				227,500,000
Available revolving credit facility				69,133,000
Outstanding irrevocable letters of credit totaling				27,067,000
New York Bonds [Member]
Debt Instrument [Line Items]
Maturity date				Dec. 18, 2044
Carrying value of bonds				25,000,000
Debt instrument interest rate				3.75%
Additional bond issued				15,000,000
Fixed Rate Bonds [Member]
Debt Instrument [Line Items]
Carrying value of bonds				398,400,000
Fair value of bonds				$ 401,861,000