Condensed Consolidated Statements of Changes in Equity - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Common stock [Member]	Additional paid-In capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss) [Member]	Non-controlling interest [Member]	Performance Share Units [Member]	Total
Balance at Dec. 31, 2015	$ 131,530	$ 27,728	$ 601,051	$ (57,133)	$ 4,183		$ 707,359
Balance, shares at Dec. 31, 2015	107,200,470
Contingently redeemable non-controlling interest, Balance at Dec. 31, 2015							24,785
Net income			63,979		272		64,251
Other comprehensive income (loss)				7,819	2		7,821
Comprehensive income			63,979	7,819	274		72,072
Net income							1,334
Other comprehensive income (loss)							169
Comprehensive Income attributable redeemable non-controlling interests							1,503
Change in value of redeemable NCI			(21,186)				(21,186)
Change in value of contingently redeemable NCI							21,186
Stock option exercises	$ 26,107	(5,405)					20,702
Stock option exercises, shares	920,798
Stock option tax adjustment		254					254
Stock option compensation expense (note 22)		4,025					4,025
Modification of PSUs (note 22)			(70)			$ 2,175	(70)
Equity-classified PSU expense (note 22)						1,222
Equity-classified PSU dividend equivalents			(20)			20	(20)
Change in value of contingently redeemable equity-classified PSUs			(21)			21	(21)
NCI acquired in a business combination (note 25)					596		596
Acquisition of NCI					(226)		(226)
Acquisition of NCI							(44,141)
Shares repurchased (note 21)	$ (36,726)						$ (36,726)
Shares repurchased, shares	(1,460,000)						0
Cash dividends paid (note 21)			(52,303)		(103)		$ (52,406)
Cash dividends paid (note 21)							(3,333)
Balance at Sep. 30, 2016	$ 120,911	$ 26,602	$ 591,430	$ (49,314)	$ 4,724		694,353
Balance, shares at Sep. 30, 2016	106,661,268
Contingently redeemable Performance share units, Balance at Sep. 30, 2016						$ 3,438	$ 3,438