Long-Term Debt (Nordea Credit Agreement) (Details) - Nordea Term Loan [Member] - USD ($)	1 Months Ended	3 Months Ended	8 Months Ended
	Sep. 30, 2014	Jun. 30, 2015	Apr. 29, 2015	Apr. 30, 2015
Debt Instrument [Line Items]
Original borrowing capacity				$ 250,000,000
Commitment fee percentage			0.875%
Debt instrument, maturity date	Apr. 30, 2020
Debt instrument, periodic payment, principal	$ 8,900,000
Debt instrument, frequency of periodic payment	quarterly
Debt instrument, periodic payment terms, balloon payment to be paid	$ 80,400,000
Interest Rate Swaps [Member]
Debt Instrument [Line Items]
Derivative, lower range of basis spread on variable rate		1.49%
Derivative, higher range of basis spread on variable rate		1.52%
Derivative, notional amount		$ 187,500,000
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		2.50%