Fair Value Measurement

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

Fair Value Measurement

Effective in 2012, we adopted a new accounting standard that expands the disclosure of our assets and liabilities disclosed, but not recorded at fair value. As of December 31, 2012 and 2011, these assets and liabilities were our held-to-maturity marketable securities and senior notes payable. The following tables summarize each class of assets and liabilities measured at fair value on a recurring basis as well as assets and liabilities that are disclosed but not recorded at fair value (in thousands):

	Fair Value Measurement at Reporting Date Using
December 31, 2012	Level 11		Level 22		Level 33		Total
Cash equivalents
Money market funds	$	201,542	$	—	$	—	$	201,542
Held-to-maturity commercial paper	5,000		—		—		5,000
Marketable securities
Held-to-maturity marketable securities	$	111,525	$	—	$	—	$	111,525
Total assets	$	318,067	$	—	$	—	$	318,067
Long-Term Debt (including current maturities)
Senior notes payable	$	—	$	—	$	243,118	$	243,118
Credit Agreement loan	—		—		70,444		70,444
Total liabilities	$	—	$	—	$	313,562	$	313,562

December 31, 2011
Cash equivalents
Money market funds	$	178,174	$	—	$	—	$	178,174
Held-to-maturity commercial paper	4,999		—		—		4,999
Marketable securities
Held-to-maturity marketable securities	149,979		—		—		149,979
Total assets	$	333,152	$	—	$	—	$	333,152
Long-Term Debt (including current maturities)
Senior notes payable	$	—	$	—	$	250,541	$	250,541
Total liabilities	$	—	$	—	$	250,541	$	250,541

¹Quoted prices in active markets for identical assets or liabilities.

²Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

³Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

A reconciliation of cash equivalents to consolidated cash and cash equivalents is as follows (in thousands):

December 31,	2012		2011
Cash equivalents	$	206,542	$	183,173
Cash	115,448		73,817
Total cash and cash equivalents	$	321,990	$	256,990

The carrying values of receivables, other current assets, and accrued expenses and other current liabilities approximate their fair values because of the short-term nature of these instruments. In addition, the fair value measured using Level 3 inputs of non-recourse debt approximates its carrying value due to its relative short-term nature and competitive interest rates. The fair values of the senior notes payable and Credit Agreement loan were based on borrowing rates available to us for long-term loans with similar terms, average maturities, and credit risk. The carrying amount of senior notes payable, including current maturities, was $208.3 million and $216.7 million as of December 31, 2012 and 2011, respectively. The carrying amount of our Credit Agreement loan was $70.0 million as of December 31, 2012. See Note 3 for the carrying amount and reporting class of held-to-maturity marketable securities as of December 31, 2012 and 2011.

We measure certain nonfinancial assets and liabilities at fair value on a nonrecurring basis. As of December 31, 2012, the nonfinancial assets and liabilities included our asset retirement obligations and our cost method investment in the preferred stock of a corporation that designs and manufactures power generation equipment. Fair value for these assets and liabilities was measured using Level 3 inputs, which are unobservable inputs supported by little or no market activity and are significant to the fair value of the assets. Asset retirement obligations were initially measured based on Level 3 fair value inputs using internal discount flow calculations based upon our estimates of future retirement costs - see Note 8 for details of the asset retirement balances.