Condensed Financial Information of Registrant Statements of Cash Flow (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ 35,439	$ (83,891)	$ 28,169	$ 61,092	$ 13,886	$ (5,822)	$ 16,178	$ 15,185	$ 40,809	$ 39,427	$ 72,621
Adjustments to reconcile net income to cash used in operating activities:
Depreciation, depletion, and amortization									86,121	52,642	45,989
Non-cash interest expense									9,118	7,127	7,276
Change in value of common stock warrants									3,199	(1,801)	1,674
Stock-based compensation									6,437	6,196	7,204
Equity in losses (income) of subsidiaries									89,751	(9,464)	(18,369)
Net changes in operating assets and liabilities:
Prepaid and other assets									(24,121)	(5,521)	37,645
Accounts payable, other accrued liabilities, and operating lease assets and liabilities									68,969	19,885	(33,780)
Net cash provided by operating activities									105,630	90,620	106,483
Cash flows from investing activities:
Capital expenditures									(83,920)	(48,439)	(31,708)
Other investing activities									864	816	35
Net cash used in investing activities									(353,229)	(175,821)	(31,673)
Cash flows from financing activities:
Proceeds from sale of common stock, net of offering costs									0	19,318	0
Proceeds from borrowings									510,906	118,741	616,706
Repayments of borrowings									(241,336)	(118,751)	(603,770)
Payment of deferred loan costs									(13,450)	(379)	(10,064)
Exercise of stock options									8,171	0	0
Payments for debt extinguishment and commitment costs									(8,087)	(3,390)	(4,432)
Other financing activities, net									582	(860)	(993)
Net cash provided by (used in) financing activities									300,208	41,943	(4,751)
Net increase (decrease) in cash, cash equivalents, and restricted cash									52,609	(43,258)	70,059
Cash, cash equivalents, and restricted cash at beginning of period				75,819				119,077	75,819	119,077	49,018
Cash, cash equivalents, and restricted cash at end of period	128,428				75,819				128,428	75,819	119,077
Net cash received (paid) for:
Interest									(58,250)	(28,186)	(23,873)
Taxes									(136)	(49)	(1,478)
Non-cash investing and financing activities:
Accrued capital expenditures									6,386	6,199	2,926
ROU assets obtained in exchange for new finance lease liabilities									963
ROU assets obtained in exchange for new finance lease liabilities										1,678	165
ROU assets obtained in exchange for new operating lease liabilities									79,382
Common stock issued for business combination									36,980	0	0
Non-cash contribution to subsidiary for business combination									(36,980)
Common stock issued to repurchase convertible notes									74,290	0	0
Parent Company
Cash flows from operating activities:
Net income (loss)									40,809	39,427	72,621
Adjustments to reconcile net income to cash used in operating activities:
Depreciation, depletion, and amortization									2,969	4,092	2,871
Non-cash interest expense									4,600	4,925	5,617
Change in value of common stock warrants									3,199	(1,801)	1,674
Stock-based compensation									6,437	6,196	7,204
Equity in losses (income) of subsidiaries									(81,097)	(81,942)	(111,162)
Debt extinguishment and commitment costs									6,091	0	1,804
Net changes in operating assets and liabilities:
Prepaid and other assets									1,592	(2,604)	(2,568)
Accounts payable, other accrued liabilities, and operating lease assets and liabilities									(8,441)	5,601	3,088
Net cash provided by operating activities									(23,841)	(26,106)	(18,851)
Cash flows from investing activities:
Investments in subsidiaries									0	0	(2,072)
Distributions from subsidiaries									16,673	0	70,645
Capital expenditures									(1,829)	(3,682)	(5,366)
Due to (from) subsidiaries									(6,519)	(25,102)	80,762
Other investing activities									31	0	0
Net cash used in investing activities									8,356	(28,784)	143,969
Cash flows from financing activities:
Proceeds from sale of common stock, net of offering costs									0	19,318	0
Proceeds from borrowings									63,406	10,770	0
Repayments of borrowings									(76,323)	(11,253)	(68,873)
Payment of deferred loan costs									(252)	0	0
Exercise of stock options									8,171	0	0
Payments for debt extinguishment and commitment costs									(1,899)	0	0
Other financing activities, net									(10)	(860)	(993)
Net cash provided by (used in) financing activities									(6,907)	17,975	(69,866)
Net increase (decrease) in cash, cash equivalents, and restricted cash									(22,392)	(36,915)	55,252
Cash, cash equivalents, and restricted cash at beginning of period				$ 29,444				$ 66,359	29,444	66,359	11,107
Cash, cash equivalents, and restricted cash at end of period	$ 7,052				$ 29,444				7,052	29,444	66,359
Net cash received (paid) for:
Interest									(5,357)	(5,750)	(7,856)
Taxes									(220)	(49)	(1,478)
Non-cash investing and financing activities:
Accrued capital expenditures									497	714	370
ROU assets obtained in exchange for new finance lease liabilities									198
ROU assets obtained in exchange for new finance lease liabilities										539	165
ROU assets obtained in exchange for new operating lease liabilities									134
Common stock issued for business combination									36,980	0	0
Common stock issued to repurchase convertible notes									$ 74,290	$ 0	$ 0