Income Taxes - (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes (Textual) [Abstract]
Portion of unrecognized tax benefit that, if recognized, would impact the effective tax rate	$ 2,300
Consolidated income (loss) subject to tax	109,300	$ (31,300)	$ 137,000
Cash paid for income taxes	2,152	$ 2,033	$ 1,657
Operating loss carryforwards	8,000
Valuation allowance	4,500
Net deferred tax asset related to tax credit carryforwards	$ 65,600
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Expiration years of net operating loss carryforwards	Dec. 31, 2017
Tax credit carryforward, expiration date	Dec. 31, 2024
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Expiration years of net operating loss carryforwards	Dec. 31, 2033
Tax credit carryforward, expiration date	Dec. 31, 2036