Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 2016

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

Compensation Costs Related to Share-Based Payments

Three months ended March 31,		2016		2015
Stock option compensation expense	$	1,070	$	723
Share unit expense		1,272		1,017
Employee share purchase plan -
employer contributions		353		308
	$	2,695	$	2,048

Summary of Stock Option Activity

					Weighted
				Weighted	average
	Common			average	remaining			Aggregate
	shares under			exercise	contractual			intrinsic
	option	price			life (in years)	value
Outstanding, December 31, 2014	3,897,791			22.09
Granted	880,706			25.50
Exercised	(1,412,535)			21.11			$	9,426
Forfeited	(89,884)			23.10
Outstanding, December 31, 2015	3,276,078			23.40
Granted	1,208,121			24.07
Exercised	(145,190)			20.88			$	632
Forfeited	(47,968)			24.49
Outstanding, March 31, 2016	4,291,041		$	23.67	7.7		$	14,985
Exercisable, March 31, 2016	2,077,964		$	22.74	5.8		$	9,028

Summary of Share Unit Activity

	Performance share units			Restricted share units			Deferred share units
			WA grant			WA grant			WA grant
			date fair			date fair			date fair
	Number		value	Number		value	Number		value
Outstanding, December 31, 2014	238,573	$	23.38	403,587	$	22.32	42,289	$	22.33
Granted	218,699		24.57	20,528		26.38	29,072		26.07
Vested and settled	(6,870)		22.22	(28,887)		22.53	(13,365)		22.34
Forfeited	(28,817)		23.23	(62,274)		21.56	-		-
Outstanding, December 31, 2015	421,585		24.03	332,954		22.70	57,996		24.21
Granted	244,536		23.19	2,214		23.33	5,749		23.40
Vested and settled	(28,543)		22.20	(124,226)		22.11	-		-
Forfeited	(28,691)		22.52	(8,127)		22.58	-		-
Outstanding, March 31, 2016	608,887	$	23.85	202,815	$	23.07	63,745	$	24.14

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

	2016	2015
Risk free interest rate	1.2%	1.8%
Expected dividend yield	2.68%	2.21%
Expected lives of the stock options	5 years	5 years
Expected volatility	26.5%	25.9%

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

	2016	2015
Risk free interest rate	1.2%	1.3%
Expected dividend yield	2.49%	2.17%
Expected lives of the PSUs	3 years	3 years
Expected volatility	29.9%	29.4%
Average expected volatility of comparable companies	37.0%	32.8%