GOODWILL AND OTHER INTANGIBLE ASSETS - Carrying Values of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	$ 2,159,545	$ 2,133,541
Accumulated Amortization	302,336	271,568
Net Value	1,857,209	1,861,973	$ 1,842,561
Operating permits
Intangible Assets By Major Class [Line Items]
Carrying Amount, Indefinite Lived Intangible Assets	231,938	229,396
Tradenames
Intangible Assets By Major Class [Line Items]
Carrying Amount, Indefinite Lived Intangible Assets	317,474	316,472
Customer relationships
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	1,575,206	1,553,398
Accumulated Amortization	291,414	261,306
Net Value	1,283,792	1,292,092
Covenants not-to-compete
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	9,360	9,491
Accumulated Amortization	6,517	6,371
Net Value	2,843	3,120
Tradenames
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	5,760	5,708
Accumulated Amortization	1,469	1,365
Net Value	4,291	4,343
Other
Intangible Assets By Major Class [Line Items]
Gross Carrying Amount	19,807	19,076
Accumulated Amortization	2,936	2,526
Net Value	$ 16,871	$ 16,550