Supplemental Guarantor/Non-Guarantor Financial Information (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from continuing operations
Net cash provided by (used in) operating activities	$ 31,939	$ 12,811
Investing activities
Purchases of property, plant and equipment	(6,405)	(4,519)
Investments in marketable securities	0	(8,159)
Maturity and redemption of investments	0	88,845
Investment in development projects	(750)	(750)
Payment of restricted cash	(6,500)	0
Other	(75)	201
Net cash provided by (used in) investing activities	(13,730)	75,618
Financing activities
Issuance of senior notes	0	200,000
Repayment of senior notes	0	(300,000)
Payment of deferred financing costs	(314)	(12,100)
Other	(408)	215
Net cash provided by (used in) financing activities	(722)	(111,885)
Net increase (decrease) in cash and cash equivalents	17,487	(23,456)
Cash and cash equivalents at beginning of period	168,745	231,633
Cash and cash equivalents at end of period	186,232	208,177
Eliminations
Cash flows from continuing operations
Net cash provided by (used in) operating activities	0	0
Investing activities
Purchases of property, plant and equipment	0	0
Investments in marketable securities	0	0
Maturity and redemption of investments	0	0
Investment in development projects	0	0
Payment of restricted cash	0	0
Other	0	0
Net cash provided by (used in) investing activities	0	0
Financing activities
Issuance of senior notes	0	0
Repayment of senior notes	0	0
Payment of deferred financing costs	0	0
Other	0	0
Net cash provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Parent Guarantor (CPE Inc.)
Cash flows from continuing operations
Net cash provided by (used in) operating activities	0	(594)
Investing activities
Purchases of property, plant and equipment	0	0
Investments in marketable securities	0	0
Maturity and redemption of investments	0	0
Investment in development projects	0	0
Payment of restricted cash	0	0
Other	0	0
Net cash provided by (used in) investing activities	0	0
Financing activities
Issuance of senior notes	0	0
Repayment of senior notes	0	0
Payment of deferred financing costs	0	0
Other	0	594
Net cash provided by (used in) financing activities	0	594
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Issuers
Cash flows from continuing operations
Net cash provided by (used in) operating activities	17,804	8,789
Investing activities
Purchases of property, plant and equipment	(703)	(833)
Investments in marketable securities	0	(8,159)
Maturity and redemption of investments	0	88,845
Investment in development projects	0	0
Payment of restricted cash	0	0
Other	0	0
Net cash provided by (used in) investing activities	(703)	79,853
Financing activities
Issuance of senior notes	0	200,000
Repayment of senior notes	0	(300,000)
Payment of deferred financing costs	(2)	(12,100)
Other	0	0
Net cash provided by (used in) financing activities	(2)	(112,100)
Net increase (decrease) in cash and cash equivalents	17,099	(23,458)
Cash and cash equivalents at beginning of period	167,532	226,993
Cash and cash equivalents at end of period	184,631	203,535
Guarantor Subsidiaries
Cash flows from continuing operations
Net cash provided by (used in) operating activities	14,134	6,825
Investing activities
Purchases of property, plant and equipment	(5,701)	(3,686)
Investments in marketable securities	0	0
Maturity and redemption of investments	0	0
Investment in development projects	(750)	(750)
Payment of restricted cash	(6,500)	0
Other	(75)	201
Net cash provided by (used in) investing activities	(13,026)	(4,235)
Financing activities
Issuance of senior notes	0	0
Repayment of senior notes	0	0
Payment of deferred financing costs	(312)	0
Other	(408)	(380)
Net cash provided by (used in) financing activities	(720)	(380)
Net increase (decrease) in cash and cash equivalents	388	2,210
Cash and cash equivalents at beginning of period	1,213	496
Cash and cash equivalents at end of period	1,601	2,706
Non-Guarantor Subsidiaries
Cash flows from continuing operations
Net cash provided by (used in) operating activities	0	(2,208)
Investing activities
Purchases of property, plant and equipment	0	0
Investments in marketable securities	0	0
Maturity and redemption of investments	0	0
Investment in development projects	0	0
Payment of restricted cash	0	0
Other	0	0
Net cash provided by (used in) investing activities	0	0
Financing activities
Issuance of senior notes	0	0
Repayment of senior notes	0	0
Payment of deferred financing costs	0	0
Other	0	0
Net cash provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents	0	(2,208)
Cash and cash equivalents at beginning of period	0	4,144
Cash and cash equivalents at end of period	$ 0	$ 1,936