Shareholders' Equity (Narrative) (Detail) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended			25 Months Ended
	Jul. 24, 2017 shares	Oct. 31, 2017 $ / shares	Sep. 30, 2017 $ / shares	Jun. 30, 2018 $ / shares shares	Jun. 30, 2017 $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Jul. 31, 2017 shares	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2018 shares	Dec. 31, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock split description						On April 26, 2017, the Company announced that its Board of Directors approved a split of its common shares on a three-for-two basis, which was approved by its shareholders at the Company's Annual and Special Meeting of Shareholders on May 23, 2017. Shareholders of record on June 7, 2017 received from the Company's transfer agent on June 16, 2017, one additional common share for every two common shares held. All share and per share amounts for all periods presented have been retroactively adjusted to reflect the share split.
Stockholders equity stock conversion ratio						1.5
Maximum number of shares authorized for repurchase	13,181,806
Share repurchase plan expiration date	Aug. 07, 2018
Daily repurchase of shares, maximum							80,287
Average daily trading volume during period							321,151
Repurchase of common stock (shares)						594,474		0
Aggregate cost of stock repurchased | $						$ 42,040
Maximum remaining number of shares available for repurchase				12,587,332		12,587,332			12,587,332
Cash dividend per share | $ / shares		$ 0.14	$ 0.12	$ 0.14	$ 0.12	$ 0.28		$ 0.24
Cash dividend per common share, increase | $ / shares		$ 0.02
Cash dividends on common stock | $						$ 73,584		$ 63,463
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of award | $ / shares						$ 69.22
Units granted in period						496,217
Vested deferred RSUs outstanding				349,799	352,263	349,799		352,263	349,799
Restricted Stock Units (RSUs) [Member] | Progressive Waste Solutions Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted in period									0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of award | $ / shares						$ 69.04
Performance period end date						Dec. 31, 2020
Units granted in period						178,377
Performance Shares [Member] | 2018 Performance Based Restricted Share Units Grant One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						3 years
Performance Shares [Member] | 2018 Performance Based Restricted Share Units Grant Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						1 year
Performance Shares [Member] | Progressive Waste Solutions Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted in period									0
Performance Shares [Member] | Maximum [Member] | 2018 Performance Based Restricted Share Units Grant Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						4 years
Employee Stock Option [Member] | Progressive Waste Solutions Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period									0
Deferred Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of award | $ / shares						$ 70.47
Units granted in period						4,038
Vested deferred RSUs outstanding				17,176		17,176			17,176	13,138