Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 2019

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

Compensation Costs Related to Share-Based Payments

Three months ended March 31,		2019		2018
Stock option compensation expense:
SG&A expenses	$	1,539		2,148
Acquisition-related costs		-		195
Share unit expense:
Equity-classified share units		2,368		3,035
Liability-classified share units		150		1,599
Employee share purchase plan -
employer contributions		553		537
	$	4,610	$	7,514

Summary of Stock Option Activity

					WA
	Common			WA	remaining			Aggregate
	shares under			exercise	contractual			intrinsic
	option	price			life (in years)	value
Outstanding, December 31, 2018	4,013,863		$	26.41	7.2		$	25,374
Granted	862,198			33.79
Exercised	(82,926)			19.61				1,302
Forfeited	(15,405)			15.83
Outstanding, March 31, 2019	4,777,730			27.89	7.5			29,190
Exercisable, March 31, 2019	2,820,624		$	25.51	6.5		$	23,943

Summary of Stock Option and Performance Share Unit Pricing Assumptions

Three months ended March 31,	2019	2018
Risk free interest rate	2.5%	2.7%
Expected dividend yield	2.06%	2.11%
Expected lives of the stock options	5 years	5 years
Expected volatility	26.8%	28.1%

Performance Share Units [Member]

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

Summary of Stock Option and Performance Share Unit Pricing Assumptions

Three months ended March 31,	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%

Summary of Share Unit Activity

	Equity-classified awards						Liability-classified awards
	PSUs			RSUs			DSUs
		WA grant			WA grant			WA grant
			date fair			date fair			date fair
	Number		value	Number		value	Number		value
Outstanding, December 31, 2018	670,288	$	31.46	207,986	$	28.99	113,435	$	28.16
Granted	155,803		36.41	25,726		36.44	6,522		36.54
Vested and settled	(231,873)		30.41	(260)		31.98	-		-
Forfeited	(1,123)		31.63	(530)		32.08	-		-
Outstanding, March 31, 2019	593,095	$	33.17	232,922	$	29.81	119,957	$	28.62