Fair value measurement (Tables)

3 Months Ended

Mar. 31, 2020

Fair value measurement

Fair Value Assets Recurring and Nonrecurring

		March 31, 2020				December 31, 2019
		Carrying				Carrying
	Category	amount		Fair value		amount		Fair value
Fair values disclosed:
Cash and cash equivalents	Level 1	$	290,094	$	290,094	$	359,671	$	359,671
Restricted cash	Level 1		65,831		65,831		60,585		60,585
Short-term debt	Level 2		33,081		33,081		4,705		4,705
Long-term debt
Senior unsecured notes	Level 1		491,381		502,813		490,933		520,625
Term loans	Level 2		139,099		139,785		154,548		155,355