Fair Value Measurements - Carrying Amounts and Estimated Fair Values by Input Level (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jan. 19, 2017
Financial liabilities:
Interest rate	5.625%
Senior notes | 5.625% Notes
Financial liabilities:
Interest rate	5.625%		5.625%
Carrying Amount | Recurring
Financial assets:
Cash and cash equivalents	$ 479,598	$ 277,953
Held-to-maturity securities	7,466
Promissory notes	16,853
Loan to the JIVDC		20,900
Financial liabilities:
Other liabilities	21,863	22,696
Carrying Amount | Recurring | Secured credit facility
Financial liabilities:
Long-term debt	1,907,932	730,787
Carrying Amount | Recurring | Senior notes | 5.625% Notes
Financial liabilities:
Long-term debt	399,332	399,249
Carrying Amount | Recurring | Other long-term obligations
Financial liabilities:
Long-term debt	104,583	119,310
Fair Value | Recurring
Financial assets:
Cash and cash equivalents	479,598	277,953
Held-to-maturity securities	7,879
Promissory notes	17,415
Loan to the JIVDC		16,533
Financial liabilities:
Other liabilities	21,857	22,696
Fair Value | Recurring | Secured credit facility
Financial liabilities:
Long-term debt	1,886,333	760,456
Fair Value | Recurring | Senior notes | 5.625% Notes
Financial liabilities:
Long-term debt	360,000	412,000
Fair Value | Recurring | Other long-term obligations
Financial liabilities:
Long-term debt	96,338	113,460
Level 1 | Recurring
Financial assets:
Cash and cash equivalents	479,598	277,953
Held-to-maturity securities	0
Promissory notes	0
Loan to the JIVDC		0
Financial liabilities:
Other liabilities	0	0
Level 1 | Recurring | Secured credit facility
Financial liabilities:
Long-term debt	1,886,333	760,456
Level 1 | Recurring | Senior notes | 5.625% Notes
Financial liabilities:
Long-term debt	360,000	412,000
Level 1 | Recurring | Other long-term obligations
Financial liabilities:
Long-term debt	0	0
Level 2 | Recurring
Financial assets:
Cash and cash equivalents	0	0
Held-to-maturity securities	7,879
Promissory notes	17,415
Loan to the JIVDC		0
Financial liabilities:
Other liabilities	2,815	0
Level 2 | Recurring | Secured credit facility
Financial liabilities:
Long-term debt	0	0
Level 2 | Recurring | Senior notes | 5.625% Notes
Financial liabilities:
Long-term debt	0	0
Level 2 | Recurring | Other long-term obligations
Financial liabilities:
Long-term debt	96,338	113,460
Level 3 | Recurring
Financial assets:
Cash and cash equivalents	0	0
Held-to-maturity securities	0
Promissory notes	0
Loan to the JIVDC		16,533
Financial liabilities:
Other liabilities	19,042	22,696
Level 3 | Recurring | Secured credit facility
Financial liabilities:
Long-term debt	0	0
Level 3 | Recurring | Senior notes | 5.625% Notes
Financial liabilities:
Long-term debt	0	0
Level 3 | Recurring | Other long-term obligations
Financial liabilities:
Long-term debt	$ 0	$ 0