Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance	$ 1,499,148	$ 736,981	$ 286,949	$ 396,528
Net income	56,520us-gaap_ProfitLoss	4,354us-gaap_ProfitLoss	35,963us-gaap_ProfitLoss
Merger Transaction	736,290	434,186
Change in pension and postretirement, net of tax	(42,113)	6,655	(500)
Exercise of stock options	603	2,613
Amendment to Directors' Deferred Compensation Plan	7,361
Stock-based compensation	5,987	493
Other	696us-gaap_StockholdersEquityOther	(4)us-gaap_StockholdersEquityOther
Repurchase of securities			(145,000)
Voting Common Stock [Member] \| Common Stock [Member] \| Performance Accelerated Restricted Stock Plan (PARS) [Member]
Performance accelerated restricted stock	(163)	(51)
Voting Common Stock [Member] \| Common Stock [Member]
Balance	1,321,011	557,754	133,000	270,511
Merger Transaction	736,290	421,703
Exercise of stock options	603	2,613
Amendment to Directors' Deferred Compensation Plan	7,361
Stock-based compensation	5,987	493
Other	696	(4)
Conversion of common stock	12,483		5,301
Repurchase of securities			(142,812)
Nonvoting Common Stock [Member] \| Common Stock [Member]
Balance		12,483		7,489
Merger Transaction		12,483
Conversion of common stock	(12,483)		(5,301)
Repurchase of securities			(2,188)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(36,445)	5,668	(987)	(487)
Change in pension and postretirement, net of tax	(42,113)	6,655	(500)
Retained Earnings [Member]
Balance	214,582	161,076	154,936	119,015
Net income	53,506	6,140	35,921
Performance Accelerated Restricted Stock Plan (PARS) [Member]
Performance accelerated restricted stock	$ (163)	$ (51)

This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

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