Statements of Condensed Consolidated Total Equity (unaudited) - USD ($) $ in Thousands	Total	Preferred shares at par value	Common shares at par value Class A common shares at par value	Common shares at par value Class B common shares at par value	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss	Class B common shares held by a subsidiary	Non-controlling interests
Balance at Dec. 31, 2015	$ 658,425	$ 0	$ 1,015	$ 181	$ 975,419	$ 16,172	$ (334,542)	$ (181)	$ 361
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,642				1,642
Exercised stock options and vested share awards	3		3		0
Repurchase of shares	(1,992)		(2)		(2,245)	255
Dividend to non-controlling interest	(97)								(97)
Comprehensive income/(losses):
Net losses attributable to common shares	(1,469)					(1,568)			99
Other comprehensive income	13,739						13,692		47
Balance at Mar. 31, 2016	670,251	0	1,016	181	974,816	14,859	(320,850)	(181)	410
Balance at Dec. 31, 2016	686,832	0	1,018	181	979,458	58,313	(352,339)	(181)	382
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,535				1,535
Exercised stock options and vested share awards	3		3		0
Comprehensive income/(losses):
Net losses attributable to common shares	(17,977)					(18,111)			134
Other comprehensive income	13,901						13,938		(37)
Balance at Mar. 31, 2017	$ 684,294	$ 0	$ 1,021	$ 181	$ 980,993	$ 40,202	$ (338,401)	$ (181)	$ 479