Income Taxes - Deferred Taxes and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Line Items]
Basis differences related to financial derivatives	$ 15,917	$ 28,395
Basis differences related to hedged items	9,307	2,866
Unrealized losses on available-for-sale securities	0	5,660
Allowance for losses	2,602	2,297
Stock-based compensation	1,648	2,833
Capital loss carryforwards and other than temporary impairment	56	2,099
Other	1,247	1,444
Total deferred tax assets	30,721	43,495
Unrealized gains on available-for-sale securities	16,889	0
Basis difference in subsidiary	23	300
Other	1,518	279
Total deferred tax liability	18,430	579
Deferred tax asset, net	12,291	42,916
Capital Loss Carryforward [Member]
Valuation Allowance [Line Items]
Valuation allowance	$ (56)	$ (2,099)