CONSOLIDATED STATEMENTS OF EQUITY Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Class C, Non-Voting [Member]	Preferred Stock [Member]	Preferred Stock [Member] Common Class C, Non-Voting [Member]	Common Stock [Member]	Common Stock [Member] Common Class C, Non-Voting [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Common Class C, Non-Voting [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Common Class C, Non-Voting [Member]	Retained Earnings [Member]	Retained Earnings [Member] Common Class C, Non-Voting [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Common Class C, Non-Voting [Member]
Beginning Balance (Shares Outstanding) at Dec. 31, 2016			8,400		10,539
Beginning Balance at Dec. 31, 2016	$ (643,647)		$ (204,759)		$ (10,539)		$ (118,655)		$ (33,758)		$ (275,714)		$ (222)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	42,694		0		0		0		0		42,694		0
Less: Net loss attributable to non-controlling interest	165		0		0		0		0		0		(165)
Other comprehensive income, net of tax	8,670		0		0		0		8,670		0		0
Dividends, Preferred Stock, Cash	6,591		0		0		0		0		6,591		0
Dividends, Common Stock, Cash	7,616		0		0		0		0		7,616		0
Stock Issued During Period, Shares, New Issues				0		65
Stock Issued During Period, Value, New Issues		$ 290		$ 0		$ 65		$ 225		$ 0		$ 0		$ 0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	1,784		0		0		1,784		0		0		0
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	(1,727)		$ 0		$ 0		(1,727)		0		0		0
Ending Balance (Shares Outstanding) at Jun. 30, 2017			8,400		10,604
Ending Balance at Jun. 30, 2017	680,929		$ 204,759		$ 10,604		118,937		42,428		304,201		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Deconsolidation	(57)		0		0		0		0		0		(57)
Cumulative Effect of New Accounting Principle in Period of Adoption	498		0		0		0		27		471		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	708,644		$ 204,759		$ 10,619		118,979		51,112		323,175		0
Beginning Balance (Shares Outstanding) at Dec. 31, 2017			8,400		10,619
Beginning Balance at Dec. 31, 2017	(708,146)		$ (204,759)		$ (10,619)		(118,979)		(51,085)		(322,704)		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	55,455		0		0		0		0		55,455		0
Less: Net loss attributable to non-controlling interest	0
Other comprehensive income, net of tax	22,298		0		0		0		22,298		0		0
Dividends, Preferred Stock, Cash	6,591		0		0		0		0		6,591		0
Dividends, Common Stock, Cash	12,347		0		0		0		0		12,347		0
Stock Issued During Period, Shares, New Issues				0		48
Stock Issued During Period, Value, New Issues		$ 55		$ 0		$ 48		$ 7		$ 0		$ 0		$ 0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	1,269		0		0		1,269		0		0		0
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	(2,571)		$ 0		$ 0		(2,571)		0		0		0
Ending Balance (Shares Outstanding) at Jun. 30, 2018			8,400		10,667
Ending Balance at Jun. 30, 2018	$ 766,212		$ 204,759		$ 10,667		$ 117,684		$ 73,410		$ 359,692		$ 0