Segment Information - Schedule of Reconciliation of Net Income to EBITDA (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Income (Loss)	$ 35,497	$ 41,976	$ 35,710	$ 31,555	$ 25,171	$ 29,471	$ 42,820	$ 37,110	$ 144,738	$ 134,572	$ 95,128
Interest (income) expense, net									(1,503)	(192)	461
Income Tax Expense (Benefit)									44,964	42,289	46,791
Depreciation and Amortization									14,031	16,597	16,860
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)									144,738	134,572	95,128
Interest (income) expense, net									(1,503)	(192)	461
Income Tax Expense (Benefit)									44,964	42,289	46,791
Depreciation and Amortization									14,031	16,467	16,730
EBITDA									202,230	193,136	159,110
Operating Segments [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)									142,811	131,823	97,412
Interest (income) expense, net									(1,496)	(192)	461
Income Tax Expense (Benefit)									44,292	41,421	47,911
Depreciation and Amortization									13,413	13,216	14,598
EBITDA									199,020	186,268	160,382
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)									1,927	2,749	(2,284)
Interest (income) expense, net									(7)
Income Tax Expense (Benefit)									672	868	(1,120)
Depreciation and Amortization									618	3,251	2,132
EBITDA									$ 3,210	$ 6,868	$ (1,272)