Fair Value Measurements (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2016

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Financial Instruments at Fair Value Based on Valuation Approach Applied to Each Class of Security

Components of long-term debt including the associated interest rates and related fair values are as follows (in thousands, except interest rates):

	March 31, 2016				December 31, 2015				Stated Interest Rate
Issuance	Face Value		Estimated Fair Value		Face Value		Estimated Fair Value
2019 Notes	$	925,000	$	929,625	$	925,000	$	879,906		6.375	%
2020 Notes		930,000		802,125		930,000		756,788		8.75	%
2022 Notes		300,000		304,909		300,000		296,296		8.875	%
Total	$	2,155,000	$	2,036,659	$	2,155,000	$	1,932,990		—

The following summarizes the financial instruments of the Company, measured at fair value on a recurring basis, based on the valuation approach applied to each class of security as of December 31, 2014 (in thousands):

	Fair Value Measurement at Reporting Date Using
	Balance at December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	1	$	1	$	—	$	—
Restricted cash equivalents:
Money market funds		14,214		14,214		—		—
Total assets	$	14,215	$	14,215	$	—	$	—

Components of Long-Term Debt Including Associated Interest Rates and Related Fair Values

Components of long-term debt including the associated interest rates and related fair values (in thousands, except interest rates):

Issuance	December 31, 2015				December 31, 2014				Stated Interest Rate
	Face Value		Estimated Fair Value		Face Value		Estimated Fair Value
2019 Notes	$	925,000	$	879,906	$	925,000	$	881,063		6.375	%
2020 Notes		930,000		756,788		930,000		792,825		8.75	%
2022 Notes		300,000		296,296		—		—		8.875	%
Total	$	2,155,000	$	1,932,990	$	1,855,000	$	1,673,888		—