Income Taxes, Current and Deferred Amounts of Income Tax Expense Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 82,449	$ 74,646	$ 50,628
State	2,560	1,000	2,653
Total current	85,009	75,646	53,281
Deferred:
Federal	(10,606)	(805)	16,409
State	7,084	10,695	9,511
Total deferred	(3,522)	9,890	25,920
Total income tax expense	$ 81,487	$ 85,536	$ 79,201