Guarantees (Details 3)	Jun. 30, 2016 USD ($)
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure, undiscounted	$ 114,600,000
Fixed maximum amounts guaranteed by year 2016	15,500,000
Fixed maximum amounts guaranteed by year 2017	35,800,000
Fixed maximum amounts guaranteed by year 2018	5,900,000
Fixed maximum amounts guaranteed by year 2019	53,400,000
No scheduled maturity date	4,000,000
Amount outstanding under guarantees that is reflected on balance sheet	0
Letters of credit	37,900,000
Letters of credit set to expire - 2016	9,600,000
Letters of credit set to expire - 2017	28,300,000
Outstanding letters of credit	0
Amount of surety bonds outstanding	787,400,000
Financial Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure, undiscounted	$ 66,000,000