Debt - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended			6 Months Ended	0 Months Ended
	Jul. 01, 2013	Mar. 31, 2010	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Jun. 05, 2014	May 31, 2014	Oct. 31, 2013	Jun. 05, 2013
Line of Credit Facility [Line Items]
Issue of cash convertible senior subordinated notes		$ 375,000,000.0
Notes bear interest rate per year		3.50%
Date of commencing of notes		Sep. 15, 2010
Deposit cash made to credit facility to repurchase convertible notes	375,000,000.0
Repayment of Knight Convertible Notes				257,700,000
Interest payable				3,600,000		3,600,000
Convertible debt			117,259,000	117,259,000		117,259,000
Convertible Notes, conversion rate (in shares)			0.0159728
Convertible Notes, conversion price (in dollars per share)			$ 62.61
Fair value of embedded conversion derivative			0	0		0
Term credit agreement			0	235,000,000		235,000,000
Cash held in collateral account				117,300,000		117,300,000
Writedown of capitalized debt costs			9,552,000	13,209,000	0
Debt issuance costs incurred			38,500,000
Secured Debt [Member]
Line of Credit Facility [Line Items]
Interest rate										8.25%
Term credit agreement										305,000,000.0
Escrow agent fees and expenses	3,000,000
Number of days to issue securities	365 days
Additional interest percent obligation from guarantor if certain obligations are not met	1.00%
Amount of consenting shareholders percentage of total debt								98.50%	99.70%
Early principal payments			235,000,000	300,000,000
Writedown of capitalized debt costs			9,600,000	13,200,000
Interest rate at end of period			9.10%
First Lien Credit Facility [Member]
Line of Credit Facility [Line Items]
Writedown of capitalized debt costs						13,200,000
First Lien Credit Facility [Member] | Jefferies Finance LLC and Goldman Sachs Bank USA [Member]
Line of Credit Facility [Line Items]
Term credit agreement	535,000,000.0
Early principal payments			235,000,000	300,000,000		300,000,000
Writedown of capitalized debt costs			9,600,000
Percentage points added to interest rate base	4.50%
First Lien Credit Facility [Member] | Jefferies Finance LLC and Goldman Sachs Bank USA [Member] | Prime Rate [Member]
Line of Credit Facility [Line Items]
Interest rate of credit agreement	2.25%
Percentage points added to interest rate base	0.50%
First Lien Credit Facility [Member] | Jefferies Finance LLC and Goldman Sachs Bank USA [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Interest rate of credit agreement	1.00%
Percentage points added to interest rate base	3.50%
First Lien Credit Facility [Member] | Jefferies Finance LLC and Goldman Sachs Bank USA [Member] | LIBOR Floor [Member]
Line of Credit Facility [Line Items]
Interest rate of credit agreement	1.25%
Revolving Credit Facility [Member] | OCTEG-KCA [Member]
Line of Credit Facility [Line Items]
Term credit agreement	450,000,000.0		0
Revolving credit facility amount	750,000,000.0
Debt issuance costs incurred			1,200,000
Number of debt instruments	2
Number of borrowing base	2
Increase in line of credit facility, maximum borrowing capacity	300,000,000.0
Commitment fee percentage of average daily amount unused portion of revolving credit agreement	0.35%
Revolving Credit Facility [Member] | Borrowing Base A [Member] | OCTEG-KCA [Member]
Line of Credit Facility [Line Items]
Percentage points added to interest rate base	1.75%
Revolving Credit Facility [Member] | Borrowing Base B Loan [Member] | OCTEG-KCA [Member]
Line of Credit Facility [Line Items]
Percentage points added to interest rate base	2.25%
Revolving Credit Facility [Member] | Jefferies Finance LLC and Goldman Sachs Bank USA [Member]
Line of Credit Facility [Line Items]
Revolving credit facility amount	50,000,000.0
Swingline Facilty [Member] | OCTEG-KCA [Member]
Line of Credit Facility [Line Items]
Revolving credit facility amount	$ 50,000,000.0
Convertible Notes [Member]
Line of Credit Facility [Line Items]
Redemption price percentage	100.00%
Secured Debt [Member]
Line of Credit Facility [Line Items]
Redemption price percentage							108.25%
Redemption period							12 months
Maximum redemption percentage of principal amount							35.00%
Secured Debt [Member] | Prior to June 15, 2015 [Member]
Line of Credit Facility [Line Items]
Redemption price percentage							100.00%
Scenario, Actual [Member]
Line of Credit Facility [Line Items]
Debt maturity date		Mar. 15, 2015
Date of mature of notes		Mar. 15, 2015
Minimum [Member] | Secured Debt [Member]
Line of Credit Facility [Line Items]
Redemption notice, period							30 days
Maximum [Member] | Secured Debt [Member]
Line of Credit Facility [Line Items]
Redemption notice, period							60 days