Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation Costs Related to Share-Based Payments

	Three months ended				Nine months ended
	September 30,				September 30,
		2018		2017		2018		2017
Stock option compensation expense:
SG&A expenses	$	2,066		2,920	$	6,354	$	6,244
Acquisition-related costs		162		-		357		4,752
Share unit expense (recovery):
Equity-classified share units		2,718		(176)		8,978		1,871
Liability-classified share units		300		821		2,245		246
Employee share purchase plan -
employer contributions		538		468		1,630		1,350
	$	5,784	$	4,033	$	19,564	$	14,463

Summary of Stock Option Activity

					WA
	Common			WA	remaining			Aggregate
	shares under			exercise	contractual			intrinsic
	option	price			life (in years)	value
Outstanding, December 31, 2017	4,459,744		$	24.29	7.5		$	17,649
Granted	914,967			32.12
Exercised	(1,154,541)			23.45			$	13,472
Forfeited	(77,644)			27.04
Expired	(1,302)			25.76
Outstanding,September 30, 2018	4,141,224		$	26.20	7.4		$	41,122
Exercisable, September 30, 2018	2,107,984		$	24.08	6.4		$	25,401

Summary of Share Unit Activity

	Equity-classified awards						Liability-classified awards
	PSUs			RSUs			PSUs			RSUs			DSUs
		WA grant			WA grant			WA grant			WA grant			WA grant
			date fair			date fair			date fair			date fair			date fair
	Number		value	Number		value	Number		value	Number		value	Number		value
Outstanding, December 31, 2017	434,248	$	27.83	125,152	$	26.93	259,241	$	26.38	4,666	$	26.42	93,487	$	26.32
Granted	235,426		35.70	90,147		32.08	-		-	66		34.70	19,448		33.36
Transferred to equity
awards on modification	257,659		31.30	-		-	(257,659)		26.38	-		-	-		-
Vested and settled	(212,263)		33.78	-		-	-		-	(975)		27.58	(6,605)		23.16
Forfeited	(43,071)		31.42	(5,219)		31.99	(1,582)		26.45	-		-	-		-
Outstanding, September 30, 2018	671,999	$	31.45	210,080	$	29.02	-	$	-	3,757	$	26.27	106,330	$	27.80

Stock Option Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock Option and Performance Share Unit Pricing Assumptions

Nine months ended September 30,	2018	2017
Risk free interest rate	2.7%	2.0%
Expected dividend yield	2.11%	2.14%
Expected lives of the stock options	5 years	5 years
Expected volatility	28.1%	27.8%

Senior Executive and Employee Performance Share Unit Plans [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock Option and Performance Share Unit Pricing Assumptions

Nine months ended September 30,	2018
Risk free interest rate	1.9%
Expected dividend yield	2.09%
Expected lives of the PSUs	3 years
Expected volatility	31.1%
Average expected volatility of comparable companies	34.1%

Sign-on Grant Performance Share Unit Plans [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock Option and Performance Share Unit Pricing Assumptions

September 11, 2018
Risk free interest rate	2.7%
Expected dividend yield	1.53%
Expected lives of the PSU	1 year
Expected volatility	29.2%