Summary of Significant Accounting Policies - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash paid:
Interest paid (net of amounts capitalized)	$ 12,289	$ 16,749	$ 17,103
Income taxes paid	11,286	105	23,553
Cash received:
Income taxes refund	6,985	7,768	0
Noncash investing and financing activities:
Acquisition of fixed assets included in accounts payable and accrued expenses	$ 2,058	$ 2,031	$ 4,822