Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Measurement [Abstract]

Fair Value Assets Recurring and Nonrecurring

		December 31, 2017					December 31, 2016
	Category		Carrying amount		Fair value		Carrying amount		Fair value
Fair values disclosed, recurring:
Cash and cash equivalents	Level 1	$	267,910	$	267,910	$	207,867	$	207,867
Restricted cash	Level 1		63,206		63,206		550,222		550,222
Short-term debt (note 25)	Level 2		7,018		7,018		23,912		23,912
Long-term debt (note 25)
Senior unsecured notes	Level 1		487,339		520,000		495,780		509,500
Revolving loans	Level 2		-		-		99,926		99,926
Delayed draw term loans	Level 2		325,553		329,687		-		-