Noncontrolling Interests Components of Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Redeemable Noncontrolling Interest [Line Items]
Total	$ 2,526	$ 22,647
Redeemable noncontrolling interests	2,526	17,461
Noncontrolling interests	0	5,186
Anchor
Redeemable Noncontrolling Interest [Line Items]
Total	0	9,761
Noncontrolling interests			$ 2,900
BOS
Redeemable Noncontrolling Interest [Line Items]
Total	0	8,057
Noncontrolling interests			$ 2,300
DGHM
Redeemable Noncontrolling Interest [Line Items]
Total	$ 2,526	$ 4,829