Other Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Equity method investment for JHJ International Transportation Co., Ltd.	$ 0	$ 22,300,000
Deferred debt costs	4,500,000	5,000,000
Prepayments	31,600,000	35,500,000
Other	18,100,000	18,100,000
Other assets	54,200,000	80,900,000
JHJ international Transportation Co. [Member]
Dividends received	$ 0	1,700,000
Excess of investment over interest in equity		$ 4,500,000