Shareholders' Equity - AOCI Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at the beginning of the period	$ 43,714	$ 26,957
Other comprehensive income (loss) before reclassifications	(1,360)	15,381
Amounts reclassified from cumulative other comprehensive income (loss) to net income	(4)	12
Net current period other comprehensive loss	(1,364)	15,393
Balance at the end of the period	42,350	42,350
Unrealized Gain on Investment in Available for Sale Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at the beginning of the period	33,216	21,074
Other comprehensive income (loss) before reclassifications	(1,032)	11,110
Amounts reclassified from cumulative other comprehensive income (loss) to net income	0	0
Net current period other comprehensive loss	(1,032)	11,110
Balance at the end of the period	32,184	32,184
Equity in Unrealized Gain of an Investee
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at the beginning of the period	10,498	5,883
Other comprehensive income (loss) before reclassifications	(328)	4,271
Amounts reclassified from cumulative other comprehensive income (loss) to net income	(4)	12
Net current period other comprehensive loss	(332)	4,283
Balance at the end of the period	$ 10,166	$ 10,166