Condensed Consolidated Statement of Equity (unaudited) - 3 months ended Mar. 31, 2018 - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in-Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Company Shares Held by SERP [Member]	Retained Earnings [Member]	Non-controlling Interest [Member]	Total
Balance at Dec. 31, 2017	$ 4,614	$ 141,931	$ (24,243)	$ (1,960)	$ 565,330	$ 1,093	$ 686,765
Balance (in shares) at Dec. 31, 2017	23,070
Net income	$ 0	0	0	0	20,267	(51)	20,216
Other comprehensive income	0	0	1,777	0	0	3	1,780
Change in ownership percentage of subsidiary	0	0	0	0	0	(43)	(43)
Dividends declared	0	3	0	0	(2,311)	0	(2,308)
Stock-based compensation	$ 0	1,581	0	0	0	0	1,581
Stock-based compensation (in shares)	0
Stock issued under incentive plans	$ 3	(3)	0	0	0	0	0
Stock issued under incentive plans (in shares)	17
Withholding tax paid upon vesting of RSUs	$ 0	(364)	0	0	0	0	(364)
SERP transactions, net	0	207	0	169	0	0	376
Other	0	0	0	0	0	73	73
Balance at Mar. 31, 2018	$ 4,617	$ 143,355	$ (22,466)	$ (1,791)	$ 583,286	$ 1,075	$ 708,076
Balance (in shares) at Mar. 31, 2018	23,087