Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax [Line Items]
Income tax expense	$ 97,019,000	$ 101,943,000	$ 79,507,000
Federal NOL carryforwards	102,194,000	131,195,000
General business tax credit carryforward	2,924,000	1,982,000
Alternative minimum tax credit carryforward	112,861,000	83,428,000
State and local income taxes, amount	$ 450,000
Decrease resulting from current period tax positions	15.00%
Effective tax rate If fully recognized	29.71%
Expiration of Statues of Limitation
Income Tax [Line Items]
Significant change in unrecognized tax benefits is Reasonably possible, amount of unrecorded benefits	$ 50,000
2013 Tax Filings
Income Tax [Line Items]
Significant change in unrecognized tax benefits is Reasonably possible, amount of unrecorded benefits	200,000
Net-worth Taxes
Income Tax [Line Items]
Income tax expense	8,100,000	$ 8,200,000	$ 9,900,000
Federal
Income Tax [Line Items]
Federal NOL carryforwards	$ 292,000,000