SCHEDULE II- VALUATION AND QUALIFYING ACCOUNTS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance, January 1	$ 1,026		$ 921		$ 686
Deconsolidation/Purchase Price Adjustment for PDCM	0		0		121
Charged to Cost and Expense	423		258		135
Deductions	188	[1]	153	[1]	21	[1]
Ending Balance, December 31	1,261		1,026		921
Valuation Allowance for Unproved Natural Gas and Crude Oil Properties [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance, January 1	8,036		12,204		16,996
Deconsolidation/Purchase Price Adjustment for PDCM	0		0		260
Charged to Cost and Expense	3,964		4,207		2,611
Deductions	6,400	[1]	8,375	[1]	7,143	[1]
Ending Balance, December 31	$ 5,600		$ 8,036		$ 12,204

[1] For allowance for doubtful accounts, deductions represent the write-off of accounts receivable deemed uncollectible. For valuation allowance for unproved crude oil and natural gas properties, deductions represent accumulated amortization of expired or abandoned unproved crude oil and natural gas properties, with a corresponding decrease to the historical cost of the associated asset.