Financial Instruments

3 Months Ended

Mar. 31, 2019

Cash and Cash Equivalents [Abstract]

Cash, Cash Equivalents and Restricted Cash

The carrying value of cash and cash equivalents approximate fair value and are as follows (in thousands):



	March 31,		December 31,
	2019		2018
As held:
Cash	$	152,676	$	136,642
Money market funds	217,258		143,843
	$	369,934	$	280,485
As reported:
Cash and cash equivalents	$	320,414	$	220,728
Restricted cash	49,520		59,757
	$	369,934	$	280,485

Restricted cash consisted of the following (in thousands):



	March 31,		December 31,
	2019		2018
Current
Restricted cash	$	13,379	$	25,740
Restricted cash related to PPA Entities	5,040		2,917
Restricted cash, current	18,419		28,657
Non-current
Restricted cash	3,250		3,246
Restricted cash related to PPA Entities	27,851		27,854
Restricted cash, non-current	31,101		31,100
	$	49,520	$	59,757

Short-Term Investments

As of March 31, 2019 and December 31, 2018, we had no short-term investments and $104.4 million in U.S. Treasury Bills, respectively.

Derivative Instruments

We have derivative financial instruments related to natural gas forward contracts and interest rate swaps. See Note 7 - Derivative Financial Instruments for a full description of our derivative financial instruments.