Debt and Interest Expense (tables)

6 Months Ended

Jun. 30, 2014

The following table presents WES’s outstanding debt as of June 30, 2014, and December 31, 2013:



	June 30, 2014						December 31, 2013
thousands	Principal		Carrying Value		Fair Value ⁽¹⁾		Principal		Carrying Value		Fair Value ⁽¹⁾
5.375% Senior Notes due 2021	$	500,000	$	495,439	$	566,283	$	500,000	$	495,173	$	533,615
4.000% Senior Notes due 2022	670,000		673,105		697,141		670,000		673,278		641,237
WES revolving credit facility	110,000		110,000		110,000		—		—		—
2.600% Senior Notes due 2018	350,000		350,537		358,515		250,000		249,718		247,988
5.450% Senior Notes due 2044	400,000		393,795		441,083		—		—		—
Total debt outstanding	$	2,030,000	$	2,022,876	$	2,173,022	$	1,420,000	$	1,418,169	$	1,422,840


⁽¹⁾	Fair value is measured using Level 2 inputs.

Debt activity. The following table presents WES’s debt activity for the six months ended June 30, 2014:



thousands	Carrying Value
Balance at December 31, 2013	$	1,418,169
Revolving credit facility borrowings	590,000
Issuance of 5.450% Senior Notes due 2044	400,000
Issuance of 2.600% Senior Notes due 2018	100,000
Repayments of revolving credit facility	(480,000		)
Other	(5,293		)
Balance at June 30, 2014	$	2,022,876

The following table summarizes the amounts included in interest expense:



	Three Months Ended June 30,						Six Months Ended June 30,
thousands	2014			2013			2014			2013
Interest expense on long-term debt	$	21,445		$	14,850		$	37,580		$	28,789
Amortization of debt issuance costs and commitment fees	1,426			1,064			2,692			2,117
Capitalized interest	(2,007		)	(3,260		)	(5,447		)	(6,441		)
Interest expense	$	20,864		$	12,654		$	34,825		$	24,465