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 January 1, 2017 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	3,149				3,149
Exercised stock options and vested share awards	16		4		12
Repurchase of shares	(1,992)		(2)		(2,245)	255
Dividend to non-controlling interest	(171)								(171)
Comprehensive income/(losses):
Net (losses)/earnings attributable to common shares	6,839					6,799			40
Other comprehensive income	4,449						4,347		102
Balance at Jun. 30, 2016	670,715	0	1,017	181	976,335	23,226	(330,195)	(181)	332
Balance at January 1, 2017 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	3,554				3,554
Exercised stock options and vested share awards	3		3		0
Comprehensive income/(losses):
Net (losses)/earnings attributable to common shares	(22,948)					(23,033)			85
Other comprehensive income	30,052						30,043		9
Balance at Jun. 30, 2017	$ 697,493	$ 0	$ 1,021	$ 181	$ 983,012	$ 35,280	$ (322,296)	$ (181)	$ 476