Consolidated balance sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 19,712	$ 48,595
Accounts receivable, net	111,573	96,515
Inventories, net	24,025	16,137
Prepaid expenses	2,754	3,998
Derivative instruments	27,797	2,152
Deferred income taxes	0	9,260
Total current assets	185,861	176,657
Property and equipment—at cost, net	68,805	69,426
Oil and natural gas properties, using the full cost method:
Proved	3,512,036	3,258,661
Unevaluated (excluded from the amortization base)	327,495	321,477
Accumulated depreciation, depletion, amortization and impairment	(1,640,113)	(1,470,090)
Total oil and natural gas properties	2,199,418	2,110,048
Derivative instruments	16,274	6,403
Other assets	32,184	35,348
Total assets	2,502,542	2,397,882
Liabilities and stockholders' equity
Accounts payable and accrued liabilities	161,302	134,811
Accrued payroll and benefits payable	26,392	24,246
Accrued interest payable	33,661	24,225
Revenue distribution payable	30,583	25,138
Current maturities of long-term debt and capital leases	5,677	5,334
Derivative instruments	246	8,234
Deferred income taxes	2,128	0
Total current liabilities	259,989	221,988
Long-term debt and capital leases, less current maturities	1,514,673	1,557,528
Derivative instruments	27	0
Stock-based compensation	5,209	4,942
Asset retirement obligations and other	43,787	53,305
Deferred income taxes	98,361	62,855
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock, 600,000 shares authorized, none issued and outstanding	0	0
Additional paid in capital	428,124	424,377
Retained earnings	152,358	72,873
Total stockholders' equity	580,496	497,264
Total liabilities and stockholders' equity	2,502,542	2,397,882
Common Class A
Stockholders' equity:
Common stock	4	0
Common Class B
Stockholders' equity:
Common stock	3	4
Common Class C
Stockholders' equity:
Common stock	2	2
Common Class D
Stockholders' equity:
Common stock	0	3
Common Class E
Stockholders' equity:
Common stock	5	5
Common Class F
Stockholders' equity:
Common stock	0	0
Common Class G
Stockholders' equity:
Common stock	$ 0	$ 0