Segment Information - Schedule of Reconciliation of Net Income to EBITDA (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net income (loss)	$ 31,555	$ 37,110
Interest (income) expense, net	(56)	229
Income tax expense (benefit)	7,700	10,415
Depreciation and amortization	3,425	4,765
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income (loss)	31,555	37,110
Interest (income) expense, net	(56)	229
Income tax expense (benefit)	7,700	10,415
Depreciation and amortization	3,394	4,733
EBITDA	42,593	52,487
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net income (loss)	31,255	37,580
Interest (income) expense, net	(56)	229
Income tax expense (benefit)	7,600	10,572
Depreciation and amortization	3,268	3,453
EBITDA	42,067	51,834
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net income (loss)	300	(470)
Income tax expense (benefit)	100	(157)
Depreciation and amortization	126	1,280
EBITDA	$ 526	$ 653