Consolidated Statements of Changes in Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Dec. 31, 2017		61,476,000
Beginning Balance at Dec. 31, 2017	$ 1,015,479	$ 122,952	$ 226,937	$ 690,674	$ (25,084)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	8,151			8,151
Other comprehensive income	9,307				9,307
Dividends declared	(16,027)			(16,027)
Share-based compensation expense, exercises and other (in shares)		336,000
Share-based compensation expense, exercises and other	2,008	$ 672	1,336
Ending Balance (in shares) at Mar. 31, 2018		61,812,000
Ending Balance at Mar. 31, 2018	$ 1,018,918	$ 123,624	228,273	682,798	(15,777)
Beginning Balance (in shares) at Dec. 31, 2018	62,294,000	62,294,000
Beginning Balance at Dec. 31, 2018	$ 518,419	$ 124,588	238,773	200,670	(45,612)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(14,096)			(14,096)
Other comprehensive income	(6,423)				(6,423)
Dividends declared	(119)			(119)
Share-based compensation expense, exercises and other (in shares)		642,000
Share-based compensation expense, exercises and other	$ 4,058	$ 1,284	2,774
Ending Balance (in shares) at Mar. 31, 2019	62,936,000	62,936,000
Ending Balance at Mar. 31, 2019	$ 501,839	$ 125,872	$ 241,547	$ 186,455	$ (52,035)