Income Taxes, Current and Deferred Amounts of Income Tax Expense Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 73,781	$ 82,449	$ 74,646
State	2,885	2,560	1,000
Total current	76,666	85,009	75,646
Deferred:
Federal	3,338	(10,606)	(805)
State	7,318	7,084	10,695
Total deferred	10,656	(3,522)	9,890
Total income tax expense	$ 87,322	$ 81,487	$ 85,536