Income Taxes (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Jun. 30, 2016	Sep. 30, 2016	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax [Line Items]
Deferred Income Tax Expense (Benefit)					$ 48,457	$ 32,090
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions					1,200	$ 100
Accounting Standards Update 2015-17
Income Tax [Line Items]
Amounts previously reported, reclassified					$ 21,600
Internal Revenue Service (IRS) | Maximum
Income Tax [Line Items]
Tax Year Closed					2011
NEW MEXICO | Maximum
Income Tax [Line Items]
Tax Year Closed					2011
TEXAS
Income Tax [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions		$ 900		$ 100
TEXAS | Earliest Tax Year
Income Tax [Line Items]
Income Tax Examination, Year under Examination					2007
TEXAS | Latest Tax Year
Income Tax [Line Items]
Income Tax Examination, Year under Examination					2011
ARIZONA
Income Tax [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities			$ 300
ARIZONA | Earliest Tax Year
Income Tax [Line Items]
Tax Year Closed	2009
ARIZONA | Latest Tax Year
Income Tax [Line Items]
Tax Year Closed	2012
Change in Accounting Method Accounted for as Change in Estimate
Income Tax [Line Items]
Deferred Income Tax Expense (Benefit)		$ 2,800