New Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Cumulative Effect Adjustments to Condensed Consolidated Statement of Financial Position [Abstract]
Deferred tax assets	$ 35,257	$ 35,257		$ 39,635
Total assets	2,452,696	2,452,696		2,409,066
Common stock	324,268	324,268		339,462
Accumulated deficit	(74,062)	(74,062)		(82,334)
Total Shareholders' Equity	246,923	246,923	$ 254,375	251,092	$ 250,371
Total Liabilities and Shareholders' Equity	2,452,696	2,452,696		2,409,066
Income tax expense (benefit)	(300)		$ (300)
ASU 2016-09 [Member]
Cumulative Effect Adjustments to Condensed Consolidated Statement of Financial Position [Abstract]
Deferred tax assets				40,882
Total assets				2,410,313
Common stock				339,524
Accumulated deficit				(81,149)
Total Shareholders' Equity				252,339
Total Liabilities and Shareholders' Equity				2,410,313
Unrealized excess benefits on share based compensation		1,230
Forfeiture provision		60
Impact to equity after consideration of deferred taxes		$ 20
Income tax expense (benefit)	$ (300)
ASU 2016-09 [Member] | Originally Presented [Member]
Cumulative Effect Adjustments to Condensed Consolidated Statement of Financial Position [Abstract]
Deferred tax assets				39,635
Total assets				2,409,066
Common stock				339,462
Accumulated deficit				(82,334)
Total Shareholders' Equity				251,092
Total Liabilities and Shareholders' Equity				2,409,066
ASU 2016-09 [Member] | Cumulative Retrospective Adjustments [Member]
Cumulative Effect Adjustments to Condensed Consolidated Statement of Financial Position [Abstract]
Deferred tax assets				1,247
Total assets				1,247
Common stock				62
Accumulated deficit				1,185
Total Shareholders' Equity				1,247
Total Liabilities and Shareholders' Equity				$ 1,247