Share-Based Payments (Summary of Stock Option Activity) (Details) - Stock Option Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding beginning balance, Common shares under option	4,459,744	3,366,714	3,276,078
Granted, Common shares under option	923,199	970,947	1,268,101
Assumed in acquisition, Common shares under option		737,358
Exercised, Common shares under option	(1,235,154)	(444,571)	(1,081,531)
Forfeited, Common shares under option	(132,624)	(170,704)	(95,934)
Expired, Common shares under option	(1,302)
Outstanding ending balance, Common shares under option	4,013,863	4,459,744	3,366,714
Exercisable, Common shares under option	2,074,873
Outstanding beginning balance, Weighted average exercise price (per share)	$ 24.29	$ 24.02	$ 23.40
Granted, Weighted average exercise price (per share)	32.14	31.07	24.34
Assumed in acquisition, Weighted average exercise price (per share)		14.26
Exercised, Weighted average exercise price (per share)	23.10	22.35	22.50
Forfeited, Weighted average exercise price (per share)	25.91	19.38	24.32
Expired, Weighted average exercise price (per share)	25.76
Outstanding ending balance, Weighted average exercise price (per share)	26.41	$ 24.29	$ 24.02
Exercisable, Weighted average exercise price (per share)	$ 24.06
Outstanding, Weighted average remaining contractual life (in years)	7 years 2 months 12 days	7 years 6 months	7 years 6 months
Exercisable, Weighted average remaining contractual life (in years)	6 years 2 months 12 days
Outstanding beginning balance, Aggregate intrinsic value	$ 17,649	$ 33,601
Exercised, Aggregate intrinsic value	14,808	3,762	$ 9,380
Outstanding ending balance, Aggregate intrinsic value	25,374	$ 17,649	$ 33,601
Exercisable, Aggregate intrinsic value	$ 17,963