Debt and Other Long-Term Liabilities (Tables)

3 Months Ended

Mar. 31, 2015

Long-term Debt, Unclassified [Abstract]

Schedule of Debt and Other Long Term Liabilities [Table Text Block]

	Debt														Other Liabilities							Total
	Senior Notes						Credit Facility					Total Debt			Capital Lease Obligations			Asset retirement obligations		Other long-term liabilities
Dollars in thousands	Senior Unsecured Notes due 2019			Senior Unsecured Notes due 2021			Term Loans			Revolving Line of Credit
As of March 31, 2015:
Principal	$	350,000		$	300,000		$	144,375		$	80,000	$	874,375
Discount	(4,041		)	(3,991		)	(317		)	—		(8,349		)
Total	345,959			296,009			144,058			80,000		866,026			$	12,652		$	12,663	$	15,292	$	906,633
Less: current portion	—			—			(10,313		)	—		(10,313		)	(9,231		)	—		—		(19,544		)
Total long-term portion	$	345,959		$	296,009		$	133,745		$	80,000	$	855,713		$	3,421		$	12,663	$	15,292	$	887,089
Unamortized deferred financing fees(1)	$	611		$	1,319		$	—		$	2,799	$	4,729									$	4,729

	Debt														Other Liabilities							Total
	Senior Notes						Credit Facility					Total Debt			Capital Lease Obligations			Asset retirement obligations		Other long-term liabilities
Dollars in thousands	Senior Unsecured Notes due 2019			Senior Unsecured Notes due 2021			Term Loans			Revolving Line of Credit
As of December 31, 2014:
Principal	$	350,000		$	300,000		$	146,250		$	160,000	$	956,250
Discount	(4,296		)	(4,152		)	(335		)	—		(8,783		)
Total	345,704			295,848			$	145,915		160,000		947,467			$	15,391		$	13,576	$	17,651	$	994,085
Less: current portion	—			—			(9,390		)	—		(9,390		)	(11,026		)	—		—		(20,416		)
Total long-term portion	$	345,704		$	295,848		$	136,525		$	160,000	$	938,077		$	4,365		$	13,576	$	17,651	$	973,669
Unamortized deferred financing fees(1)	$	649		$	1,372		$	—		$	2,965	$	4,986									$	4,986

(1) Deferred financing fees are recorded in other long-term assets in our Consolidated Balance Sheets and are amortized on a straight line basis over the life of the related loan.

Interest Expense Disclosure [Table Text Block]

Interest Expense

Dollars in thousands	Three Months Ended
	March 31,
	2015		2014
Cash interest expense	$	11,395	$	8,362
Non-cash interest expense:
Amortization of debt discount	435		802
Amortization of deferred financing fees	258		504
Total non-cash interest expense	693		1,306
Total interest expense	$	12,088	$	9,668

Schedule of Maturities of Long-term Debt [Table Text Block]

The Amended and Restated Credit Agreement requires principal amortization payments under the Term Loan as follows:

Dollars in thousands	Repayment Amount
Remainder of 2015	$	7,500
2016	13,125
2017	15,000
2018	18,750
2019	90,000
Total	$	144,375