Fair Value Measurement - Fair Values of Our Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	[1]	$ 548	$ 36
Derivative liabilities	[1]	373	524
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	[1]	0	0
Derivative liabilities	[1]	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	[1]	548	36
Derivative liabilities	[1]	373	524
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	[1]	0	0
Derivative liabilities	[1]	$ 0	$ 0

[1] Based on observable market transactions of spot and forward rates