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ASSET RETIREMENT OBLIGATIONS AND RESTRICTED CASH (Tables)
 12 Months Ended
Dec. 31, 2017
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Change in Asset Retirement Obligation
The following table summarizes the Company’s asset retirement obligations:
 
December 31, 2017
 
December 31, 2016
Asset retirement obligation, beginning of period
$
17,033

 
$
8,573

 Revision of estimate
249

 
4,186

 Acquired in asset acquisitions or business combinations
—

 
5,454

 Accretion of liabilities
1,733

 
906

 Settlements
(735
)
 
(2,086
)
Asset retirement obligation, end of period
$
18,280

 
$
17,033

Asset retirement obligation:
 
 
 
 Current
$
32

 
$
32

 Non-current
18,248

 
17,001

Asset retirement obligation, end of period
$
18,280

 
$
17,033
Schedule of Restricted Cash and Cash Equivalents
The following table summarizes the Company’s restricted cash:
 
December 31, 2017
 
December 31, 2016
Restricted cash, beginning of period
$
23,175

 
$
12,980

 Restricted cash from acquisitions
—

 
4,532

 Refunds of collateral
(14,657
)
 
—

 Additional collateral posted
13,609

 
5,663

Restricted cash, end of period
$
22,127

 
$
23,175