Segment Information - Schedule of Reconciliation of Net Income to EBITDA (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net income (loss)	$ 20,098	$ 7,787	$ 76,829	$ 55,217
Interest	59	77	515	1,108
Taxes	10,208	$ 2,702	39,715	27,871
Depreciation and amortization			12,065	$ 10,893
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income (loss)	20,098		76,829
Interest	59		515
Taxes	10,208		39,715
Depreciation and amortization	4,520		11,968
EBITDA	34,885		129,027
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net income (loss)	20,173		76,904
Interest	59		515
Taxes	10,208		39,715
Depreciation and amortization	3,639		11,087
EBITDA	34,079		128,221
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(75)		(75)
Depreciation and amortization	881		881
EBITDA	$ 806		$ 806