Segment Information - Schedule of Reconciliation of Net Income to EBITDA (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net income (loss)	$ 29,471	$ 20,098	$ 109,401	$ 76,829
Interest, net	222	(59)	(377)	(515)
Taxes	9,829	10,208	34,657	39,715
Depreciation and amortization			13,164	12,065
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income (loss)	29,471	20,098	109,401	76,829
Interest, net	(222)	59	377	515
Taxes	9,829	10,208	34,657	39,715
Depreciation and amortization	3,769	4,520	13,067	11,968
EBITDA	42,847	34,885	157,502	129,027
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net income (loss)	27,755	20,173	107,449	76,904
Interest, net	(222)	59	377	515
Taxes	9,259	10,208	34,009	39,715
Depreciation and amortization	3,275	3,639	10,004	11,087
EBITDA	40,067	34,079	151,839	128,221
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net income (loss)	1,716	(75)	1,952	(75)
Taxes	570		648
Depreciation and amortization	494	881	3,063	881
EBITDA	$ 2,780	$ 806	$ 5,663	$ 806