Short-Term Borrowings (Details) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 31, 2015	Mar. 31, 2017	Dec. 31, 2016	Oct. 31, 2015
Short-term Debt [Line Items]
Short-term borrowings		$ 422,924,000	$ 525,842,000
Interest rates on short-term borrowings outstanding		1.37%	1.77%
Bank loans [Member]
Short-term Debt [Line Items]
Short-term borrowings		$ 326,496,000	$ 372,301,000
Bank Overdrafts [Member]
Short-term Debt [Line Items]
Short-term borrowings		14,500,000	10,300,000
Floating Rate Puttable Notes [Member]
Short-term Debt [Line Items]
Short-term borrowings		96,428,000	96,455,000
Secured Revolving Loan Facility [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Short-term borrowings		$ 0	$ 57,086,000
Credit facility maximum amount				$ 50,000,000.0
Secured Revolving Loan Facility [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Short-term Debt [Line Items]
Debt instrument, basic spread on variable rate	4.25%	3.75%
Loan Facility [Member] | Line of Credit [Member]
Short-term Debt [Line Items]
Credit facility maximum amount	$ 50,000,000.0
Intraday Credit Facility [Member] | Line of Credit [Member]
Short-term Debt [Line Items]
Credit facility maximum amount		$ 250,000,000.0
Intraday Credit Facility [Member] | Line of Credit [Member] | Federal Funds Effective Swap Rate [Member]
Short-term Debt [Line Items]
Debt instrument, basic spread on variable rate		0.50%