Fair Value Measurement - Schedule of Fair Value Measurement of Debt Instrument (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	$ 815,473	$ 534,764
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	821,073	541,707
Lines of Credit | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	406,800	197,000
Lines of Credit | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	406,800	197,000
Syndicated Term Loans | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	191,375	169,344
Syndicated Term Loans | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	191,375	169,344
Bank Term Loans | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	79,046	30,739
Bank Term Loans | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	78,921	32,692
Notes Payable | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	35,653	32,781
Notes Payable | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	35,238	32,568
Solar Asset-Backed Notes | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	102,599	104,900
Solar Asset-Backed Notes | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt Instrument, Fair Value	$ 108,739	$ 110,103