Segment Reporting - Reconciliation of Operating Profit (Loss) from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of income from continuing operations from segments to consolidated [Abstract]
Total consolidated operating income	$ 12,189	$ (3,929)	$ (7,046)	$ 21,312	$ 21,721	$ 15,089	$ 18,750	$ 18,526	$ 22,526	$ 74,086	$ 61,943
Interest expense									(25,102)	(7,355)	(8,148)
Non-operating income, net									4,521	1,859	2,239
Income before income taxes									$ 1,945	$ 68,590	$ 56,034