Equity - AOCI Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Changes in the balances of each component of AOCI
Balance at the beginning of the period	$ 437,775	$ 840,093
Total other comprehensive income (loss), net of tax	38	24
Balance at the end of the period	421,798	827,957
Accumulated Other Comprehensive Income
Changes in the balances of each component of AOCI
Balance at the beginning of the period	1,820	1,812
Total other comprehensive income (loss), net of tax	38
Balance at the end of the period	1,858	$ 1,836
Foreign Currency Translation
Changes in the balances of each component of AOCI
Balance at the beginning of the period	1,836
Total other comprehensive income (loss), net of tax	11
Balance at the end of the period	1,847
Unrealized Gains (Losses) on Available for Sale Securities
Changes in the balances of each component of AOCI
Balance at the beginning of the period	(16)
Total other comprehensive income (loss), net of tax	27
Balance at the end of the period	$ 11