Segment Information - Schedule of Reconciliation of Net Income to EBITDA (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Net income (loss)	$ 37,110	$ 27,949
Interest	229	204
Taxes	10,415	13,747
Depreciation and amortization	4,765	$ 3,764
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income (loss)	37,110
Interest	229
Taxes	10,415
Depreciation and amortization	4,733
EBITDA	52,487
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net income (loss)	37,580
Interest	229
Taxes	10,572
Depreciation and amortization	3,453
EBITDA	51,834
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(470)
Taxes	(157)
Depreciation and amortization	1,280
EBITDA	$ 653