Fair Value Measurements (Summary of Financial Assets and Liabilities Accounted for at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets:
Investments in marketable securities	$ 155,846	$ 90,209
Derivatives	5,508	4,908
Liabilities:
Derivatives	7,217	101
Successor
Assets:
Investments in marketable securities	155,846
Derivatives	7,339
Total assets	163,185
Liabilities:
Derivatives	7,217
Successor | Level 1
Assets:
Investments in marketable securities	64,100
Derivatives	0
Total assets	64,100
Liabilities:
Derivatives	7,263
Successor | Level 2
Assets:
Investments in marketable securities	91,746
Derivatives	1,985
Total assets	93,731
Liabilities:
Derivatives	26
Successor | Level 3
Assets:
Derivatives	5,354
Total assets	5,354
Liabilities:
Derivatives	$ (72)
Predecessor
Assets:
Investments in marketable securities		90,209
Derivatives		4,908
Total assets		95,117
Liabilities:
Derivatives		101
Predecessor | Level 1
Assets:
Investments in marketable securities		2,137
Derivatives		262
Total assets		2,399
Liabilities:
Derivatives		(8)
Predecessor | Level 2
Assets:
Investments in marketable securities		88,072
Total assets		88,072
Liabilities:
Derivatives		0
Predecessor | Level 3
Assets:
Derivatives		4,646
Total assets		4,646
Liabilities:
Derivatives		$ 109