Fair Value Measurements and Disclosures (Details) - Fair Value - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets and Liabilities at Fair Value
Total assets	$ 28,610	$ 14,338
Total liabilities	137,109	101,645
Net asset (fair value)	(108,499)	(87,307)
Significant Other Observable Inputs (Level 2)
Assets and Liabilities at Fair Value
Total assets	22,467	12,949
Total liabilities	122,133	90,569
Net asset (fair value)	(99,666)	(77,620)
Significant Unobservable Inputs (Level 3)
Assets and Liabilities at Fair Value
Total assets	6,143	1,389
Total liabilities	14,976	11,076
Net asset (fair value)	$ (8,833)	$ (9,687)